WATERPROOFING 
ENGINEERING 


FOR 


Engineers,  Architects,  Builders,  Roofers 
and  Waterproofers 


BY 
JOSEPH  ROSS,   B.S.,   C.E. 

WATERPROOFING   ENGINEER 


FIRST  EDITION 


NEW  YORK 

JOHN   WILEY  &   SONS,   INC, 

LONDON:  CHAPMAN  &  HALL,  LIMITED 
1919 


COPYRIGHT,  1919 

BY 
JOSEPH  ROSS 


PRESS  OF 

BRAUNWORTH   &  CO. 

BOOK   MANUFACTURERS 

BROOKLYN,   N.  Y. 


k  t. 


PREFACE 


WATERPROOFING  engineering  is  not  taught  in  any  college,  and 
the  writers  of  engineering  papers  descriptive  of  engineering  works 
only  rarely  embody  information  on  waterproofing.  In  general,  this 
branch  of  engineering  is  given  far  too  little  consideration  and  study 
in  the  laboratory  and  in  construction.  Its  importance  warrants 
a  better  acquaintance  with  its  laws  than  exists  among  those  most 
vitally  interested.  To  remedy  this  condition  and  seemingly  to 
supply  a  real  need  to  the  profession,  I  commenced,  early  in  1914, 
a  systematic  search  and  diligent  study  of  existing  literature  on 
the  subject  of  waterproofing.  The  field  was  large  but  the  harvest 
surprisingly  small.  Secrecy  is  the  keynote  in  nearly  all  commercial 
literature  on  waterproofing;  but  with  the  aid  of  chemistry  much 
of  this  was  dispelled.  The  technical  literature  is  often  but  semi- 
illuminating,  though  some  excellent  papers  and  reports  have  been 
read  before  various  engineering  societies.  In  fact,  the  impression 
gained  from  perusing  the  literature  extant  on  waterproofing  was, 
that  the  subject  seemed  to  be  regarded  as  a  sort  of  necessary  evil  in 
engineering,  to  be  overcome  as  best  as  the  exigency  of  the  case  would 
permit,  and  if  this  failed  to  try  again  and  again  until  successful. 
The  cost  of  waterproofing  was  often  the  last  consideration,  but 
it  invariably  became  the  least  in  the  mad  effort  to  successfully 
waterproof  the  more  important  structures.  This  attitude  is  funda- 
mentally and  morally  wrong  and  economically  unsound,  because 
we  may  find  it  expedient  to  justify  our  ignorance,  but  never 
profitable. 

In  writing  this  book  it  is  believed  that  my  extensive  practical 
experience  and  experimental  research  work  in  waterproofing  engi- 
neering has  qualified  me  to  undertake  this  task,  the  magnitude  of 
which  has  not  been  underestimated.  Much  thought  and  labor 
were  devoted  to  the  task  of  compiling  and  simplifying  the  text  so 
as  to  make  it  understandable  by  all  interested  in  the  subject  of 
waterproofing,  which  interest,  fortunately,  is  gradually  increasing 
among  engineers,  architects  and  contractors. 

An  effort  is  also  made  to  explain  past  and  present  methods  and 

iii 


iv  PREFACE 

materials  of  waterproofing;  investigate  their  efficiency;  draw 
helpful,  if  not  perfectly  exact  conclusions,  and,  where  possible, 
establish  standard  methods  and  materials  for  general  waterproofing; 
and  lastly,  to  emphasize  the  value  of  careful  study  of  the  whole 
subject  by  engineers,  especially  those  engaged  in  design. 

In  the  hope  that  it  will  engender  new  thought  and  investigation, 
and  in  the  belief  that  waterproofing  engineering  is  now  coming  into 
its  own,  this  book  is  dedicated  to  the  engineering  profession. 

It  has  been  found  impracticable  in  many  cases  to  acknowledge 
due  indebtedness,  for  material  used,  to  those  writing  in  technical 
and  engineering  society  journals  on  waterproofing;  I  herewith  extend 
to  all  my  grateful  thanks. 

Most  kind  acknowledgment  for  valuable  assistance  and  sugges- 
tions are  due  and  gratefully  given  to  Mr.  Percy  S.  Palmer,  C.E., 
Mr.  William  F.  Holzschuch,  C.E.,  Mr.  Samuel  G.  Margies,  C.E., 
Mr.  Max  Miller,  C.E.,  and  particularly  to  Mr.  Raymond  J. 
Reddy,  who,  besides  contributing  information  gained  from  practical 
experience,  has  been  of  great  assistance  in  the  preparation  of  the 
manuscript  and  drawings.  I  also  take  pleasure  in  acknowledging 
my  indebtedness  to  and  esteem  for  Mr.  George  L.  Lucas,  General 
Inspector  of  Materials  of  the  Public  Service  Commission,  1st  Dist. 
of  New  York,  in  whose  department  the  opportunity  and  material 
for  writing  this  book  were  secured. 

JOSEPH  Ross. 
NEW  YORK, 

November,  1918. 


CONTENTS 


CHAPTER  I 

NEED  AND  FUNCTION  OF  WATERPROOFING 

PAGE 

Introduction  1 

Conditions  Creating  Necessity  of  Waterproofing 1 

Waterproofing — The  Universal  Structural  Bodyguard 2 

Density  for  Watertight  Concrete 3 

Source  and  Location  of  Ground  Water,  and  Its  Effect  on  Concrete 5 

Waterproofing  and  Drainage  as  a  Protection  against  Ground  Water 5 

Ineffectiveness  of  Weep  Holes  in  Preventing  Cracks  in  Masonry 6 

Causes  and  Effects  of  Porosity  in  Concrete 7 

Effect  of  Freezing  Water  on  Concrete 7 

Effect  of  Sewage'  and  Sea  Water  on  Concrete 8 

Destructive  Effect  of  Electrolysis  on  Concrete 9 

Elimination  of  Electrolytic  Effects 10 

Effect  of  Temperature  Changes  on  Concrete 11 

Effect  of  Expansion  Joints  in  Masonry 12 

Effect  of  Uneven  Settlement  on  Masonry 13 

Hygienic  Need  of  Waterproofing 13 

CHAPTER  II 

SYSTEMS  OF  WATERPROOFING 

Progress  of  the  Art  of  Waterproofing 17 

Surface    Coating    System    of    Waterproofing:     Definition,    Purpose    and 

Development 18 

Methods  of  Applying  Surface  Coatings 19 

Preparation  of  Masonry  Surface  Prior  to  Application  of  Coating 21 

Application  of  Slush,  Scratch  and  Finishing  Coats 22 

Materials  Used  for  Surface  Coatings 23 

Application  of  Cement  Mixtures 23 

Use  of  Lean  and  Rich  Mortars 25 

Application  of  Powdered  Metal 27 

The  Sylvester  Process '. 28 

Application  of  Paraffin 28 

Application  of  Bituminous  Compounds 29 

Membrane  System  of  Waterproofing:  Definition,  Purpose  and  Development  31 

Surface  Preparation  Prior  to  Application  of  Membrane 33 

Necessity  of  Continuity  of  Membrane 34 

Protection  of  Membrane 35 

v 


vi  CONTENTS 

PAGE 

Methods  of  Applying  Membrane  Waterproofing 40 

Making  Membrance  Mats 42 

Connecting  New  and  Old  Membranes 42 

Placing  Membranes  around  Projections  and  in  Vicinity  of  Steam  Pipes ...  43 

Use  of  Special  Membranes 45 

Considerations  for  Selecting  Membrane  Reinforcement 46 

Storing  and  Unrolling  Felt  and  Fabric 48 

Precautions  when  Heating  Coal-tar  Pitch  and  Asphalt 49 

Proper  Use  of  Kettles  and  Fuel  when  Heating  Pitch  or  Asphalt 50 

Differentiating  between  Coal-tar  Pitch  and  Asphalt  in  the  Field 51 

Coal-tar  Pitch  Versus  Asphalt  for  Waterproofing 51 

Mastic  System  of  Waterproofing:  Definition,  Purpose  and  Development.  .  52 

Applying  Mastic  Waterproofing 53 

Precautions  when  Joining  New  and  Old  Brick-in-Mastic 57 

Placing  Mastic  around  Projections  and  in  Vicinity  of  Steam  Pipes 57 

Preparation  of  Wall  Surfaces  for  Brick-in-Mastic 58 

Precautions  for  Setting-up,  Filling  and  Stripping  Forms  for  Brick-in-Mastic 

Walls 59 

Settlement  and  Bracing  of  Brick-in-Mastic  Walls 61 

Materials  for  Making  Mastic — Their  Properties  and  Proportions 62 

Hand  Versus  Machine-made  Mastic 63 

Brick-heating  Methods 65 

Weather  Conditions  Governing  Waterproofing  Operations 66 

Integral  System  of  Waterproofing:   Definition,  Purpose  and  Development  66 

Limitations  of  the  Integral  System  of  Waterproofing 68 

Integral  Waterproofing  Materials  and  Their  Application 69 

Use  of  Hydrated  Lime 69 

Use  of  Inert  Fillers 70 

Use  of  Active  Fillers 72 

Use  of  Proprietary  Cements 72 

Use  of  Integral  Liquids 74 

Use  of  Integral  Pastes 75 

Self-densified  Concrete :  Definition,  Purpose  and  Development 76 

Methods  of  Making  Dense  Concrete 77 

Scientific  Proportioning 78 

Grade  of  Workmanship  and  Supervision  Necessary  for  Watertight  Concrete  81 

Grouting  Process  of  Waterproofing:  Definition,  Purpose  and  Development  82 

Application  of  Grout  for  Waterproofing 84 

Cement  and  Sand  for  Grouting 85 

Equipment  for  Grouting  Process 86 

Steam  Pressure  Concrete  Mixing  and  Placing  Machine 89 

CHAPTER  III 
IMPERVIOUS  ROOFING 

Impervious  Roofing  Defined 91 

Properties  and  Application  of  Shingles 92 

Wood  Shingles 92 

Slate  Shingles 93 


CONTENTS  Vii 

PAGE 

Tile  Shingles 95 

Prepared  Shingles 100 

Asbestos  Shingles 101 

American  Method  of  Applying  Asbestos  Shingles 103 

Hexagonal  and  French  Methods  of  Applying  Asbestos  Shingles 103 

Tin  Roofing 105 

Properties  and  Application  of  Tin  Roofing 105 

Felt  (or  Composition,  or  Built-up)  Roofing 108 

Applying  Felt  Roofing 108 

Varieties  of  Prepared  or  Ready  Roofings 112 

Applying  Ready  Roofings 114 

Roof  Flashings  116 

Roof  Gutters 118 

Functional  Roofings 12Q 

Definition;  Use  and  Varieties  of  Functional  Roofings 120 

CHAPTER  IV 

WATERPROOFING  EXPANSION  JOINTS  IN  MASONRY 

Function  and  Properties  of  Expansion  Joints 124 

Monolithic  Construction  Obviates  Expansion  Joints 125 

Design  .and  Spacing  of  Expansion  Joints 126 

Joints  in  Brick  Masonry 126 

The  Slip-tongue  and  Plane-of- Weak-Bond  Joints 127 

Illustrations  of  Expansion  Joints 128 

Cut-offs  in  Expansion  Joints 134 

Physical-acting  Expansion  Joint  Fillers , 140 

Chemical-acting  Joint  Fillers 143 

CHAPTER  V 
WATERPROOFING  MATERIALS 

Selection  and  Adaptability  of  Materials    145 

Materials  for  Different  Systems  of  Waterproofing 145 

Nature  of  Materials  Acting  Chemically  as  Waterproofing  Agents 147 

Nature  of  Materials  Acting  Mechanically  as  Waterproofing  Agents 153 

CHAPTER  VI 
WATERPROOFING  IMPLEMENTS  AND  MACHINERY 

Applicability  of  Tools  and  Machinery  for  Waterproofing 166 

Varieties  of  Mastic  Mixers 166 

Varieties  of  Heating  Kettles 170 

Sundry  Waterproofing  Implements 176 

The  Cement  Gun 184 

The  Grouting  Machine 186 


viii  CONTENTS 

CHAPTER  VII 

TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING 

PAGE 

Necessity  of  Testing  Waterproofing  Materials 188 

Significance  and  Description  of  Technical  Tests  on  Bitumens 189 

Specific  Gravity 190 

Flash  Point 191 

Solubility  in  Carbon  Bisulphide 192 

Solubility  in  Carbon  Tetrachloride 194 

Solubility  in  Petrolic  Ether 194 

Penetration  Test 195 

Methods  of  Determining  Melting-points  of  Bitumens 197 

Ductility  Test  on  Bitumen 209 

Evaporation  Test  on  Bitumen 212 

Determination  of  Free  Carbon  in  Coal-tar  Pitch ' . . .  214 

Ash  Test 217 

Fixed  Carbon  Test 217 

Paraffin  Test 218 

Dimethyl  Sulphate  Test 219 

Tests  on  Treated  and  Untreated  Cement  Mortar  and  Concrete 219 

Standard  Instructions  for  Permeability  Tests 220 

Description  of  Standard  Apparatus 221 

Method  of  Testing  Permeability  of  Waterproofed  Concrete 222 

Results  of  Permeability  Tests  on  Waterproofed  Concrete 224 

Results  of  Permeability  Tests  on  Plain  Concrete 227 

Description  and  Results  of  Practical  Tests 229 

Test  on  Absorption  of  Concrete 229 

Test  on  Concrete  Floor  Hardeners 231 

Comparison  of  Melting-points  of  Bitumens 235 

Effect  of  Heat  on  Various  Pitches  Mixed  with  Linseed  Oil 236 

Flowing  and  Bonding  Properties  of  Pitch  Containing  Small  Quantities  of 

Asphalt  or  Linseed  Oil 238 

Effect  of  Asbestos  Filler  on  the  Physical  Properties  of  Bitumen 238 

Ductility  of  Asphalt  Containing  Coal-tar  Pitch 240 

Effect  of  Temperature  on  Penetration  and  Ductility  of  Asphalt  and  Coal- 
tar  Pitch  241 

Comparative  Tests  on  Coal-tar  and  Asphalt  Mastics 247 

Volume  Reduction  of  Asphalt  Mastics 248 

Mastic  Bond  Affected  by  Surface  Condition  of  Bricks 249 

Relative  Compression  of  Plain  Brick,  Brick  and  Mortar,  and  Brick-in-Mastic  249 

Effect  of  Temperature  of  Saturants  on  Waterproofing  Fabrics 251 

Relative  Amount  of  Saturant  and  Coating  Material  on  Treated  Water- 
proofing Felts  and  Fabrics 252 

Effect  of  Drinking  Water  on  Waterproofing  Fabrics 254 

Effect  of  Ground  Water  on  Waterproofing  Fabrics 255 

Relative  Absorption  and  Strength  of  Raw  and  Treated  Waterproofing  Felts 

and  Fabrics 256 

Immutability  Test  on  Various  Waterproofing  Felts  and  Fabrics 260 

Compressibility  of  Treated  Jute-fabric  Waterproofing  Membranes 260 


CONTENTS  ix 

CHAPTER  VIII 

WATERPROOFING  SPECIFICATIONS 

PAGE 

Specification  Requisites 262 

Specifications  for  Waterproofing-Materials  263 

Specifications  for  Waterproofing  Concrete  and  Masonry  Structures 273 

Specifications  for  Waterproofing  Tunnels  and  Subways 280 

Specifications  for  Waterproofing  Railroad  Structures. 293 

Specifications  for  Waterproofing  Concrete  Floors 305 

Specifications  for  Waterproofing  Roofs 306 

CHAPTER   IX 
PRACTICAL  RECIPES  AND  SPECIAL  FORMULAS 

Origin  and  Nature  of  Special  Formulas 313 

Masonry  Treatments •. 314' 

Treatments  for  Tanks 317 

Floor  Treatments .  319 

Roofings 319 

Waterproof  Cements 320 

CHAPTER  X 

WATERPROOFING  APPLIED 

Examples  of  Surface-coating  Applications 323 

Examples  of  Membrane  Applications 331 

Examples  of  Mastic  Applications 353 

Examples  of  Integral  Waterproofing  Applications 356 

Examples  of  Self-densified  Concrete  Applications 356 

Examples  of  Grouting  Applications 357 

Examples  of  Special  Waterproofing  Applications 360 

» 
CHAPTER  XI 

COST  DATA  ON  MATERIALS,  IMPLEMENTS,  AND  LABOR 

Planning  and  Estimating 368 

Importance  of  Accurate  Estimates     368 

Accurate  Estimates  Dependent  on  Accurate  Methods 369 

Labor  and  Materials - 370 

Waterproofing  Labor,  Contractors  and  Manufacturers  Graded 370 

Cost  Data  Tables 371 

CHAPTER  XII 
PRACTICAL  TABLES 

Explanation  of  Tables 379 

Thermometric  Equivalents 380 

Specific  Gravities  and  Degrees,  Baume,  for  Liquids  Heavier  and  Lighter 

than  Water..  381 


X  CONTENTS 

PAGE 

Specific  Gravity  and  Coefficient  of  Expansion-of  Various  Materials 387 

Weight  and  Thickness  of  Burlap,  Felt,  and  Cotton  Fabric  Membranes  with 

Coal-tar  Pitch  Binder 388 

Thickness  of  Waterproofing  Materials  Required  for  Different  W7ater 

Pressures 389 

Volumes  and  Weights  of  Ingredients  Used  in  Brick-in-  (Asphalt)  Mastic 

Waterproofing 390 

Pressure  Exerted  by  Water  Beneath  Floors  and  against  Walls 392 

Approximate  W7eights  and  Thicknesses  of  Various  Sheet  Metals  for  Roof, 

Gutters  and  Flashings 393 

Weights  of  Roof  Coverings 395 

Square  Feet  Covered  by  1000  Wooden  Shingles 396 

Number  of  Slates  and  Pounds  of  Nails  Required  for  Roofing £97 

Size,  Length,  Gauge  and  Weight  of  Roofing  Nails 397 

APPENDIX  I 

Explanation  of  Mechanical  Analysis  for  Grading  Concrete  Aggregates 399 

APPENDIX   II 
Concrete  in  Sea  Water 403 

APPENDIX   III 
Report  on  Waterproofing — American  Society  for  Testing  Materials 408 

APPENDIX  IV 
Glossary  of  Terms  Used  in  the  Waterproofing  Industry 413 

APPENDIX   V 
References 423 

INDEX.  .  428 


WATERPROOFING  ENGINEERING 


CHAPTER  I 
NEED  AND  FUNCTION   OF  WATERPROOFING 

INTRODUCTION 

THE  art  of  waterproofing,  while  having  passed  its  infancy,  is 
not  yet  in  its  adult  stage  of  development.  That  it  has  developed 
from  a  crude  understanding  and  practice  is  evident  from  the  fact 
that  the  ancient  Romans  would  waterproof  their  structures  by 
building  foundation  walls  so  thick  that  water  could  not  possibly 
percolate  through  them. 

Searching  through  both  ancient  and  modern  annals  for  a  his- 
tory of  the  subject,  we  are  consistently  confronted  by  the  scarcity 
of  reliable  literature  on  waterproofing;  but  it  is  quite  well  ascer- 
tained that  the  early  Egyptians  used  asphalt  *  to  waterproof  the 
foundations  of  the  pyramids,  that  they  waterproofed  the  ground 
floors  of  some  houses  by  internal  and  external  applications  of  bitu- 
minous material,  and  used  it  also  in  the  construction  of  cisterns, 
silos,  and  other  works  where  waterproofing  was  necessary:  that  the 
Romans  were  among  the  first  to  apply  successfully  the  early  prin- 
ciples of  waterproofing  and  were  the  first  successful  manufacturers 
of  hydraulic  cement.  This  cement  was  a  natural  cement  similar 
to  our  present  day  puzzolan  cement.  Of  course,  waterproofing 
engineering  as  practiced  by  both  the  Egyptians  and  Romans  must 
be  taken  in  a  restricted  sense,  for  the  art,  as  now  developed  and  as 
we  comprehend  it  to-day,  was  quite  unknown  then. 

Conditions  Creating  Necessity  of  Water  roofing.  It  has  been 
quite  definitelv  proven  that  water  is  practically  a  universal 
solvent;  i.e.,  given  time  and  water,  especially  sub-surface  water, 
very  few  things  will  resist  the  deteriorating  effect  of  the  latter.  At 

*  For  earliest  history  of  asphalt,  see:  "  Manufacture  of  Varnishes  and  Kindred 
Industries  "  by  Livache  and  Mclntosh,  Vol.  2,  p.  3D. 


••* "  *- ." 

ENGINEERING 

certain  distances  below  ground  surface,  varying  both  seasonally 
and  locally,  water  is  nearly  (within  several  feet)  at  the  same  level 
(called  ground-water  level)  throughout  the  year.  All  engineering 
structures,  of  course,  have  their  foundations  in  earth  or  rock  (which 
is  the  same  thing  so  far  as  water  pressure  is  concerned)  and  may  be 
partly  or  entirely  submerged  by  ground  water;  consequently  they 
are  subject  to  considerable  water  pressure  and  to  the  disintegrating 
influences  of  the  acids  or  alkalies  usually  present  in  ground  water. 
It  is  also  evident  that  due  to  uneven  settlement  and  continual 
variations  of  temperature,  cracks  may  develop  in  superstructural 
and  subsurface  masonry,  foundation  walls,  etc.,  through  which  water 
will  seep  regardless  of  how  minute  these  cracks  may  be;  hence 
waterproofing  in  some  form  becomes  essential  to  the  life  and  sta- 
bility of  the  structure.  What  this  form  of  waterproofing  should  be 
is  a  problem  not  susceptible  to  precise  mathematical  solution,  but 
by  a  careful  study  of  conditions  and  with  the  help  of  past  and  present 
experience,  and  a  knowledge  of  the  chemical  and  physical  properties 
of  waterproofing  materials,  a  form  or  method  can  be  devised  suitable 
for  any  special  condition.  Therefore,  a  knowledge  of  all  manner  of 
waterproofing  systems  and  the  properties  of  suitable  materials 
becomes  indispensable,  at  least  to  the  engineer  and  architect,  who 
usually  specify  how  and  what  should  be  used  under  given  conditions 
or  for  particular  structures. 

Waterproofing — The  Universal  Structural  Bodyguard.  Our  era 
has  rightly  been  designated  the  "  Concrete  Age."  In  fact,  the 
growth  of  our  civilization  might  be  measured  by  the  quantity  produc- 
tion of  cement,  and  the  commercial  progress  of  a  community  might 
be  measured  by  the  number  and  size  of  the  concrete  structures 
within  its  boundaries.  In  the  not  distant  past,  most  solid  struc- 
tures were  composed  of  ordinary  brick  or  stone  masonry,  and  to-day 
not  a  few  are  similarly  constructed,  but  these  are  rapidly  being  super- 
seded by  concrete  and  steel.  Even  for  dwellings  concrete  is  becoming 
more  adaptable  and  is  being  used  more  every  day,  and  the  prediction 
is  made  that  the  future  will  see  a  predominance  of  concrete  buildings 
of  all  varieties. 

But  co-ordinately  with  the  use  of  concrete,  or  nearly  so,  is  the 
provision  of  a  "  body  guard  "  in  the  form  of  waterproofing.  For, 
as  iron  and  steel  must  be  protected  from  corrosion,  so  must  concrete 
be  protected  from  disintegration,  but  unlike  the  former,  concrete 
must  also  be  made  impermeable.  Water,  by  its  capacity  of  alternate 
freezing  and  thawing,  reacting  upon  concrete  as  ordinarily  made, 
with  its  inherent  porosity,  wherein  water  may  lodge  and  exert  its 


NEED  AND  FUNCTION  OF  WATERPROOFING       3 

expansive  or  disintegrating  forces,  is  the  bane  of  such  structures. 
On  the  other  hand,  water  pressure  is  an  added  bane  of  subsurface 
structures.  All  of  these  causes  and  their  effects  preclude  the  possi- 
bility of  making  a  permanently  element-resisting  structure  without 
some  form  of  protection.  Waterproofing  affords  this  protection. 
Efficient  waterproofing  is  therefore  rightly  co-ordinate  with  concrete, 
the  universal  structural  material,  and  the  materials  used  to  accom- 
plish this  should  therefore  be  classed  as  structural  materials.  Water- 
proofing not  only  protects  but  prolongs  the  life  of  any  structure 
to  which  it  has  been  properly  applied.  Proper  waterproofing 
materials  intelligently  and  adequately  applied  is  the  keynote  of 
success  in  making  all  engineering  structures  watertight.  But  even 
appropriate  materials  unsystematically  applied,  or  vice  versa,  will 
not  produce  a  waterproof  medium.  This  emphasizes  the  necessity 
of  knowing  all  the  related  factors  in  waterproofing  a  structure  as 
well  as  in  designing  it. 

Density  for  Watertight  Concrete.  In  the  making  of  concrete  it 
is  attempted  to  duplicate  natural  stone,  in  form,  design  and  color, 
but  especially  in  density.  The  density  of  average  concrete  is  more 
nearly  equal  to  that  of  the  lighter  stones  (see  Table  I),  though  in 
practice  the  effort  is  universal  to  make  it  approach  that  of  the  heavier 
ones,  which  effort  has  the  desirable  effect  of  reducing  its  porosity. 
To  accomplish  this,  engineers  often  and  rightly  resort  to  scientific 
proportioning  of  the  aggregates,  increased  time  of  mixing,  careful 
tamping,  spading  and  closer  supervision  of  construction,  or  again, 
by  incorporating  certain  water-repellent  or  void-filling  ingredients 
in  mass  concrete  or  in  the  mortar  used  for  laying  up  the  stone 
masonry.  Where  these  precautions  are  impossible  or  inadequate, 
the  structure  may  be  placed  in  or  surrounded  with  an  impervious 
bituminous  sheet-layer  or  membrane,  forming  an  external  water- 
proofing medium. 

From  Table  I  it  is  evident  that  not  only  concrete  but  all  kinds 
of  stone  are  more  or  less  porous.  Hence  this  property,  being  inherent 
in  all  stones,  must  not  be  overlooked  in  construction  work  where 
it  may  cause  damage.  But  this  is  especially  true  of  concrete, 
because,  as  is  obvious  from  the  table,  it  is  very  difficult  to  make 
ordinary  concrete  denser  than  average  limestone,  and  consequently, 
its  porosity  being  always  present,  is  more  menacing  to  the  integrity 
of  any  concrete  structure. 

Ordinary  concrete  will  absorb  water  more  readily  than  is  generally 
supposed.  The  presence  of  alkaline,  such  as  magnesium  or  sodium 
sulphate,  or  of  acid  in  ground  water,  tends  to  attack  the  cement  in 


4  WATERPROOFING   ENGINEERING 

some  manner  not  yet  definitely  known,  and  is  one  of  the  chief  causes 
for  the  disintegration  of  concrete.  This  is  especially  true  of  the 
action  of  sea  water  on  concrete.  Other  causes  tending  to  disintegrate, 
or  in  some  manner  to  disrupt  concrete,  are  electrolysis,  temperature 
changes  and  uneven  settlement.  A  brief  review  will  be  made  of  each 
of  these  causes  and  their  effects. 


TABLE   I.— AVERAGE  WEIGHTS,    SPECIFIC    GRAVITIES,   AND    AB- 
SORPTION OF  VARIOUS  STONES  AND  CONCRETES 

STONE 


Kind  of  Stone. 

Weight, 
Lb.  per 
Cu.  Ft. 

Specific 
Gravity. 

Water 
Absorbed,* 
Lb.  per  Cu.  Ft. 

Trap 

180 

2  92 

Max.         Min. 
1  03      0  23 

Marble          

170 

2  72 

1  04      0  10 

Slate                                  .    . 

168 

2  70 

2  10      0  05 

Granite 

168 

2  70 

2  77      0  04 

Limestone   

162 

2  60 

6  62      0  02 

Conglomerate  

162 

2  60 

3  71       0  60 

Sandstone 

150 

2  40 

11  60      0  02 

Brick  

125 

1.85 

18  .  75       

Gravel   

100 

2  65 

Cinders 

95 

1  50 

CONCRETE 


Kind  of  Aggregate. 

Weight, 
Lb.  per 
Cu.  Ft. 

Specific 
Gravity. 

Water 
Absorbed, 
Lb  per  Cu.  Ft.*  t 

Trap                      

155 

2  48 

3.13 

Conglomerate 

150 

2  40 

Gravel.  

150 

2.40 

3.66 

Limestone        

148 

2.34 

3.47 

Marble 

144 

2  30 

2  48 

Sandstone 

143 

2  29 

Cinders 

112 

1  79 

9  61 

*  For  exact  method  of  determining  absorption  of  water  per  cubic  foot  of  rock,  see 
American  Society  of  Civil  Engineers  Transactions,  Vol.  82,  p.  1437  (1918). 

t  The  figures  in  the  last  column  were  estimated  from  tests  made  on  6-inch  cubes  of  1 :  2  :  4 
concrete. 


NEED  AND  FUNCTION  OF  WATERPROOFING  5 

SOURCE  AND  LOCATION  OF  GROUND  WATER  AND  ITS  EFFECT  ON 

CONCRETE 

Since  water  is  the  all-important  cause  creating  the  necessity  for 
waterproofing,  we  will  consider  briefly  its  source  and  general  loca- 
tion in  the  ground. 

Ground  water  is  that  part  of  rain,  hail  or  snow  that  has  percolated 
through  and  accumulated  in  the  ground  as  water,  either  in  soil  or 
in  rock,  usually  in  consequence  of  an  underlying  impervious  stratum 
which  materially  retards  or  totally  prevents  its  further  percolation 
downward.  The  upper  surface  of  ground  water  is  called  the  water 
table,  or  the  ground-water  level.  The  depth  of  ground-water  level 
below  the  earth's  surface  varies  with  the  locality,  topography  and 
character  of  the  earth's  material.*  Ground-water  level  has  nothing 
to  do  with  mean  high  water,  though  in  some  localities  they  are  at 
the  same  elevation;  the  latter  surface,  however,  is  usually  lower. 
Proper  drainage  will,  of  course,  lower  ground-water  level,  and  this 
is  often  resorted  to  in  order  to  obviate  the  need  of  more  extensive 
waterproofing.  But  as  the  limit  of  this  level  is  mean  high-water 
level,  its  successful  possibilities  are  not  unlimited.  So  far  as  water- 
proofing is  concerned,  therefore,  the  two  water  levels  require  equal 
consideration,  because  one  or  the  other,  or  both,  are  always  operative. 
A  clause  in  the  specifications  for  waterproofing  the  new  subways 
in  New  York  reads:  "  waterproofing  cf  the  structure  will  be  limited 
to  the  roof  and  to  those  surfaces  near  ground  water,  or  mean  high 
water,  if  ground-water  level  is  found  for  any  reason  to  be  below  mean 
high  water."  Flood  water  is  less  difficult  to  control  than  either 
sea  or  ground  water,  and  only  affects  certain  localities  at  certain 
times,  often  due  to  accident.  Its  effects  are  readily  overcome  by 
proper  drainage,  damming  or  simple  waterproofing  methods. 

Waterproofing  and  Drainage  as  a  Protection  against  Ground 
Water.  The  most  general  effect  of  ground  water  on  engineering 
works  is  to  necessitate  these  works  being  constructed  with  special 
waterproofing  considerations.  The  earth  below  ground-water  level 
remains  wet  constantly,  often  subjecting  an  underground  structure 
to  a  large  hydrostatic  head.  It  is  this  head  of  water  which  requires 
careful  attention  and  design  to  make  it  effective.  And  what  can- 
not be  accomplished  by  design  -alone  can  be  accomplished  by  inclu- 
ding a  system  of  waterproofing  to  prevent  the  percolation  of  water 
through  the  more  or  less  porous  concrete,  or  through  slight  cracks 
that  may  develop  in  it. 

*  Turneaure  and  Russell,  "  Public  Water  Supply." 


6  WATERPROOFING  ENGINEERING 

An  underground  system  of  drainage  is  often  included  even  where 
a  complete  system  of  waterproofing  is  called  for  and  provided,  as  in 
the  above  cited  subway  specification,  to  wit:  "Every  part  of  the 
railroad  must,  so  far  as  possible,  be  so  arranged  that  any  water 
finding  access  thereto  will  be  led  away  automatically  to  the  city 
sewers.  Where  the  railroad  is  on  an  inclined  gradient,  and  is  con- 
structed in  dry,  porous  soil,  the  floor  of  the  railroad  may  be  depended 
on  to  act  as  a  conduit.  At  the  bottom  of  the  inclined  gradient 
connection  must  be  made  with  a  sewer  or  with  subdrains  lying 
beneath  the  railroad  and  draining  into  the  sewers. 

"  Along  such  parts  of  the  work  where  the  soil  is  not  porous,  or 
where  the  floor  of  the  railroad  cannot,  in  the  judgment  of  the  engineer, 
be  used  as  a  conduit  there  shall  be  laid,  beneath  the  rail  level  and  on  a 
continuous  descending  gradient,  drain  pipes  of  vitrified  tile.  Each 
drain  shall  be  laid  in  the  concrete  or  directly  in  the  soil  with  tight 
or  open  joints,  as  directed,  and  in  such  manner  and  in  such  position 
as,  in  the  opinion  of  the  engineer,  local  circumstances  require." 

Ineffectiveness  of  Weep  Holes  in  Preventing  Cracks  in  Masonry. 
Concrete  retaining  walls  and  abutments,  but  more  especially  the 
former,  are,  as  a  rule,  provided  with  weep  holes  to  take  care  of  the 
water  at  their  backings.  The  practice  adhered  to  is  to  let  one  weep 
hole  3  or  4  inches  in  diameter  suffice  for  every  3  or  4  yards  of  wall 
front.  But  experience  has  demonstrated  that  such  weep  holes 
do  not  always  suffice  to  protect  a  wall  against  water  pressure  (in 
so  far  as  it  affects  percolation),  still  less  against  deteriorating  agencies 
in  the  water,  and  least  of  all  do  they  prevent  surface  disfiguration 
due  to  efflorescence.  Neither  do  weep  holes  prevent  subsequent 
and  uneven  settlement  with  consequent  cracking  of  the  masonry. 
The  reason  is  quite  obvious;  for  weep  holes  too  often  and  too  easily 
become  clogged,  and  are  in  consequence  unable  to  carry  off  the 
storm  water  rapidly,  which  is  their  main  function,  consequently  the 
water  accumulates  in  the  backfill  and  backs  up  behind  the  wall, 
causing,  with  the  aid  of  head  and  frost,  the  damages  referred  to 
above. 

While  waterproofing  would  not  overcome  all  of  these  defects, 
it  would  undoubtedly  eliminate  to  a  marked  degree  their  effects. 
In  fact,  the  tendency  in  present-day  construction  is  to  eliminate 
weep  holes  and  substitute  a  type  of  waterproofing  meeting  the 
purpose  and  need  of  the  structure.  Thus  it  is  seen  that  ground 
water  is  the  elemental  cause  against  which  concrete  structures  must 
be  protected  by  the  application  of  some  waterproofing  material  or 
drainage  system,  or  both. 


NEED  AND  FUNCTION  OF  WATERPROOFING 


CAUSES  AND  EFFECTS  OF  POROSITY  IN  CONCRETE 

Cement  mortar  and  concrete,  even  when  made  under  laboratory 
conditions,  are  far  from  being  dense  enough  to  completely  pre- 
vent the  percolation  (independent  of  absorption)  of  water  through 
them  if  time  is  reckoned  as  a  factor.  The  volume  of  total  voids 
in  mortars  averages  about  26  per  cent,  and  in  concrete,  of  pro- 
portions commonly  employed  in  practice,  the  voids  range  from 
13  to  17  per  cent.  That  this  is  a  common  as  well  as  a  serious 
condition  follows  from  the  fact  that  many  laboratory  tests  show 
that  70  to  80  per  cent  of  the  tempering  water  evaporates, 
leaving  behind  it  the  cells  that  it  formerly  occupied,  and  as  these 
cells  are  more  or  less  connected,  a  system  of  ducts  through  the 
entire  structure  is  established.  This  cellular  condition  creates 
a  natural  capillary  passageway  for  water  to  enter  and  be  absorbed 
in  the  mass.  But  the  permeability  of  mortar  or  concrete  is 
practically  independent  of  that  form  of  porosity  wherein  the  voids 
form  an  unconnected  system ,  but  the  freezing  effect  is  quite  different, 
and  is  referred  to  below. 

At  this  point  it  is  probably  well  to  remind  the  reader  not  to 
confound  porosity  with  either  permeability  or  absorption,  for  con- 
crete may  be  porous  and  yet  absorb  little  water,  and  it  may  be 
absorptive,  and  yet  not  permeable. 

Porosity  of  concrete  may  be  defined  as  the  net-work  of  uncon- 
nected voids  or  honeycombing  of  its  mass  by  the  entrained  air  and 
water. 

Absorption  of  concrete  is  the  property  of  drawing  in  or  engrossing 
water  into  its  pores  or  voids  by  capillary  action  or  otherwise. 

Permeability  (or  percolation)  of  concrete  may  be  defined  as  that 
quality,  due  to  cracks  or  connected  voids,  which  permits  the  flow  of  a 
liquid  through  it. 

Effect  of  Freezing  Water  on  Concrete.  All  three  states,  that  is 
porosity,  permeability  and  absorption,  are  allied,  and  each  one  in 
some  way  is  detrimental  to  concrete,  for,  whether  water  is  entrained 
in  the  mass  *  or  flows  through  it,  or  is  absorbed  by  the  concrete, 
when  it  freezes  some  form  of  damage  is  done.  There  are  but  few 
bonds  strong  enough  to  resist  the  expansive  force  of  freezing  water. 
It  increases  its  bulk  approximately  10  per  cent,  and  the  consequent 
expansive  force  is  probably  more  than  10,000  pounds  per  square  inch. 
A  section  of  concrete  100  feet  long,  under  100  deg.  Fahr.  (55.5  deg. 
Cent.)  change  in  temperature,  will  contract  or  expand  T%6^  of  an 
*  See  striking  example  in  Engineering  News,  Vol.  77,  No.  9,  p.  356. 


8  WATERPROOFING  ENGINEERING 

inch.  This  change  is  infinitesimal  in  comparison  to  the  volumetric 
change  in  freezing  water;  hence  the  need  for  eliminating  the  porosity 
of  concrete  and  also  preventing  the  percolation  of  water  through  it. 
For  evidence  of  the  effect  of  the  expansive  force  of  freezing  water, 
one  need  but  observe  the  physical  condition  of  natural  stones  exposed 
to  the  elements  for  a  more  or  less  protracted  period  of  time.  Even 
mountains,  with  their  proverbial  strength,  are  crippled  by  this  agency. 
A  very  striking  example  of  the  effect  of  this  tremendous  mechanical 
force  is  seen  in  the  crumbling  of  the  exposed  portions  of  the  rocky 
Palisades  on  the  New  Jersey  shore  of  the  Hudson  River. 

Effect  of  Sewage  and  Sea  Water  on  Concrete.*  That  the  dura- 
bility of  concrete  is  materially  impaired  by  its  porosity  is  strikingly 
illustrated  by  the  easy  prey  it  falls  to  the  action  of  alkali  waters, 
sewage  and  sea  water. 

The  alkalies  contained  or  formed  by  or  in  these  waters,  which 
are  most  active  in  causing  disintegration  of  concrete,  especially 
when  allowed  to  penetrate  into  the  interior  of  the  mass,  are  the 
sulphates  of  sodium,  magnesium,  and  calcium. 

Disintegration  of  concrete  in  sewers  and  sewage  disposal  works, 
whether  due  to  the  use  of  poor  materials,  poor  workmanship,  or  lean 
mixtures,  each  of  which  tends  to  decrease  the  density  of  concrete, 
has  been  found  to  take  place  above  the  normal  surface  of  the  liquid 
contained.  This  action  probably  results  from  the  fact  that  quanti- 
ties of  hydrogen  sulphide  are  evolved  from  the  sewage.  This  sul- 
phide is  produced  in  two  ways:  (a)  By  the  bacterial  decomposition 
of  sulphur-containing  proteins  and  related  compounds,  and  (6)  the 
reduction  of  sulphates  which  are  contained  in  unusual  amounts  in 
some  water  supplies.  Of  the  two,  the  second  seems  to  be  more 
important.  The  hydrogen  sulphide  which  escapes  as  gas  from  the 
sewage  is  partially  dissolved  in  the  moisture  on  the  under  side  of  the 
roof  and  concrete  walls.  Here  it  is  oxidized  to  sulphuric  acid  partly 
by  atmospheric  oxidation  and  partly  by  bacterial  action.  The 
sulphuric  acid  acts  upon  the  calcium  compounds  in  the  concrete, 
forming  calcium  sulphate,  thus  breaking  down  the  concrete. 

Where  the  effect  of  sea  water  on  concrete  has  been  other  than 
mechanical,  it  is  probable  that  disintegration  is  caused  by  the  sub- 
stitution of  magnesium  oxide  (MgO)  from  the  sea  water  in  the  place 
of  the  calcium  oxide  (CaO)  of  the  cement,  as  well  as  to  the  decrease 
in  the  proportion  of  silica  and  the  increase  in  sulphuric  anhydride 
(SOs).  Interesting  examples  of  these  processes  will  be  found  in 
Engineering  and  Contracting,  Vol.  57,  No.  26,  p.  580.  The  United 
States  Bureau  of  Standards,  after  some  extensive  tests  on  the  "  action 
*  American  Railway  Engineering  Association,  Vol.  14,  p.  834. 


NEED  AND  FUNCTION  OF  WATERPROOFING       0 

of  the  salts  in  alkali  water  and  sea  water  on  cements,"  described  in 
Technologic  Paper  No.  12  of  the  Bureau,  remarks  as  follows: 

"  The  cause  of  the  disintegration  of  cement  structures  is  not 
certain,  though  it  is  almost  universally  believed  that  it  is  the  reaction 
of  sulphate  of  magnesia  of  the  sea  water  with  the  lime  and  the 
alumina  of  the  cement,  resulting  in  the  formation  of  hydrated 
magnesia  and  calcium  sulpho-aluminate,  which  crystallizes  with  a 
large  number  of  molecules  of  water.  Other  constituents  of  sea 
water,  especially  sodium  chloride  and  magnesium  chloride,  have  also 
been  noticed  to  attack  the  silicates  of  the  cement  and  produce  rapid 
disintegration." 

To  safeguard  concrete  structures  against  the  destructive  action 
of  the  above  agents,  it  is  necessary  to  make  dense,  impermeable 
concrete  by  the  use  of  a  well-graded  aggregate,  moderately  rich 
mixture,  proper  consistency  and  good  workmanship,  and  allowing 
the  concrete  to  harden  under  favorable  conditions  before  being 
exposed;  or,  where  practicable,  by  applying  a  surface  mortar  coat 
from  1  to  2  inches  thick.  Both  of  these  methods  are  included  in 
distinct  systems  of  waterproofing,  which  are  explained  in  Chapter  II. 
In  Appendix  II  will  be  found  more  explanatory  information  on  this 
interesting  phenomenon.  For  experimental  confirmation  the  reader 
is  referred  to  the  above  Technologic  Paper. 

DESTRUCTIVE  EFFECT  OF  ELECTROLYSIS  ON  CONCRETE 

In  the  principle  of  electrolysis  we  have  a  very  formidable 
agent  at  work  against  the  integrity  of  concrete  structures;  one 
that  requires  careful  study  and  attention  in  structural  design 
and  during  construction.  Its  effect  is  mechanical  and,  though 
not  widespread,  is  as  disastrous  as  the  freezing  of  water  in 
concrete.  The  passage  of  an  electric  current  through  reinforced 
concrete  causes,  amongst  other  effects,  oxidation  of  the  iron  rein- 
forcement. The  oxides  formed  occupy  2.2  times  as  great  a  volume 
as  the  original  iron  and  the  pressure  resulting  from  this  increase 
of  volume  is  very  great.  That  it  is  possible  to  damage  re- 
inforced concrete  structures  by  stray  currents  from  electric 
railways,  power-houses,  and  general  ground  connections  is  an 
established  fact.*  Electric  currents  passing  from  the  reinforcing 
material  into  the  concrete — for  electrolytic  action  takes  place  only 
where  the  current  leaves  the  conductor — cause  corrosion  of  the 
reinforcement  and  cracking  of  the  surrounding  concrete  more  or 
less  seriously,  but  always  sufficiently  to  permit  the  percolation  of 
water  through  it,  which  further  aids  electrolysis;  this,  in  turn, 
*  Technologic  Paper  No.  18  of  the  Bureau  of  Standards,  U.  S.  A. 


10 


WATERPROOFING  ENGINEERING 


creates  more  cracks,  thus  permitting  more  water  to  enter  and  attack 
the  reinforcement,  whence  the  action  is  further  enlarged  until  there 
arises  serious  danger  that  rupture  may  ensue.* 

Elimination  of  Electrolytic  Effects.  Partial  elimination  of  elec- 
trolysis is  possible  by  the  selection  of  courses  of  masonry  or  con- 
crete of  a  high  specific  resistance  and  their  careful  distribution  about 
the  structure.  As  an  illustration:  If  blocks  of  granite  are  inter- 
posed between  the  footings  of  a  building  and  the  soil,  the  tendency 
of  the  building  to  pick  up  stray  currents  is  materially  reduced  because 
of  the  high  electrical  resistance  of  the  granite.  It  may  be  impractic- 
able to  take  these  precautions,  but  it  is  nearly  always  possible  to 
surround  the  footings  with  a  waterproofing  membrane  which  will 
accomplish  the  desired  end.  See  Fig.  1. 

Various  proportioned  concrete  aggregates  offer  greater  or  less 
resistance  to  electrolysis  with  a  showing  in  favor  of  what  would 
ordinarily  be  called  a  poor  concrete. 

Table  II  f  shows  the  specific  resistance  of  concrete  made  of  Old 
Dominion  cement,  river  sand  and  crushed  trap.  The  specific  resist- 
ance of  concrete  will,  of  course,  vary  greatly  with  the  aggregate, 
method  of  making,  etc.,  and  the  values  given  below  are  indicative 
only  of  the  order  of  magnitude  of  the  specific  resistance  that  may  be 
expected. 

TABLE  II.— ELECTRICAL  RESISTANCE  OF  MORTAR  AND  CONCRETE 


Proportion 
of  Mortar. 

Resistance 
in  Ohms  cm.3 

Proportion 
of  Concrete. 

Resistance 
in  Ohms  cm.3 

Neat  cement 

3500 

1  :2!  :4 

8000 

1  :2 

2300 

1:3    :  5 

8200 

1  :4 

2100 

1:4:7 

9900 

In  general,  complete  protection  from  electrolytic  effects  is  not 
practically  possible  by  any  other  means  than  efficient  waterproofing. 
What  form  of  waterproofing  should  be  used  for  this,  purpose  depends 
on  local  conditions  and  the  type  of  structure,  but  invariably  that 
system  which  is  of  a  membraneous  nature  will  be  most  efficient. 
Precautionary  measures  against  electrolysis  must  be  taken  both 
in  the  city  and  in  the  country,  but  perhaps  more  so  in  the  country 
because  electrical  feeders  are  usually  much  better  protected  in  cities, 
where  laws  are  enacted  for  this  purpose. 

*  Engineering  News,  Vol.  66,  June  8,  August  3  and  17,  1911;  Vol.  68,  July  12, 
December  19,  1912. 

t  Technologic  Paper  No.  18  of  the  Bureau  of  Standards,  U.  S.  A. 


NEED  AND  FUNCTION  OF  WATERPROOFING 


11 


EFFECT  OF  TEMPERATURE  CHANGES  ON  CONCRETE 

A  fourth  disrupting  force,  and  one  not  easily  overcome,  is 
change  of  atmospheric  temperature,  to  which  influence  can  be 
ascribed  many  concrete  failures.  Additional  steel  embedded  near 


Waterproofing 
Membrane 


Grillage 


Foundation 


C.I.  Manhole  Cover. 


8  Brick- 
— Waterproofing  Membrane- 

4  "Brick  Protection- 
— Hollow  Tile  Protection 


FIG.   1. — Methods  of  Waterproofing  around  Column  Bases  and  Footings  to 

Prevent  Electrolysis. 


the  surface  of  the  concrete  is  one  of  the  means  employed  to  combat 
this  force.  The  effect  of  the  temperature  change,  however,  is 
never  wholly  lost,  especially,  though  rarely,  where  concrete  is 
depended  upon  to  take  tensile  stress.  Just  to  illustrate:  Assuming 


12  WATERPROOFING  ENGINEERING 

the  coefficient  of  expansion  of  concrete  as  .0000055  per  deg.  Fahr., 
and  its  modulus  of  elasticity  as  2,000,000  pounds  per  square  inch, 
then  the  stress  due  to  temperature  is  11  pounds  per  square  inch  per 
degree  change  of  temperature,  or,  for  60  deg.  Fahr.  it  is  660  pounds 
per  square  inch,  which  is  double  the  ultimate  unit  tensile  stress  for 
concrete.  A  temperature  difference  between  summer  and  winter  of 
twice  60  deg.  Fahr.  is  not  uncommon  in  certain  parts  of  the  United 
States.*  Fortunately,  in  this  country,  tensile  strength  of  concrete 
is  neglected.  It  must  not  be  supposed,  however,  that  steel  rein- 
forcement, however  efficiently  placed,  does  more  than  diminish 
the  size  and  distribute  the  cracks  which  are  caused  by  temperature 
changes.  But  this  result  is  sufficient  to  materially  increase  the 
impermeability  of  the  structure. 

Effect  cf  Expansion  Joints  in  Masonry.  In  steel,  a  change  of 
temperature  of  1  deg.  Fahr.  causes  a  stress  of  about  200  pounds  per 
square  inch  if  resisted.  In  concrete  a  change  of  18  deg.  Fahr.  causes 
an  equal  stress  if  likewise  resisted;  that  is,  if  expansion  joints  are 
not  provided  to  take  care  of  the  expansion  and  contraction,  the 
resulting  stresses  may  cause  cracks  in  the  structure,  with  the  usual 
result  cf  disfigurement  due  to  efflorescence  and  damage  due  to  seepage. 
But,  on  the  other  hand,  these  very  expansion  joints  create  one  of  the 
most  urgent  needs  for  waterproofing  a  concrete,  or  for  that  matter, 
any  form  of  masonry  structure. 

Expansion  and  contraction  in  a  structure  and  their  resulting 
stresses  are  due  to  changes  in  atmospheric  temperature  or  change 
in  temperature  of  the  concrete  while  it  is  setting  and  hardening. 
This  latter  temperature  change  may  be  as  high  as  150  deg.  Fahr., 
depending  on  the  thickness  of  the  masonry,  f  With  steel  rein- 
forcement to  take  care  of  stresses  resulting  from  temperature 
change,  the  cracks  are  kept  small,  but  not  entirely  prevented.  The 
expansion  joints  necessary  to  relieve  the  atmospheric  Jbemperature- 
change-stresses  require  special  study.  Their  form  and  location  in  a 
structure  not  only  have  a  great  bearing  on  the  stresses  set  up  in  it  but 
also  on  their  effectiveness.  While  expansion  joints  tend  to  relieve  the 
effects  of  these  stresses,  they  are  not  always  effective  in  preventing 
hair  cracks  or  cracks  at  angles  in  the  structure,  or  leakage  through 
the  joints  themselves  as  commonly  constructed.  Hence  the  need  of 
an  efficient  type  of  waterproofing,  in  conjunction  with  well-designed 
expansion  joints,  > which  together  will  most  effectively  overcome 
these  defects. 

*  American  Civil  Engineers'  Pocket  Book,  2d  Edition,  p.  1255. 

t  Taylor  and  Thompson,  "Concrete,  Plain  and  Reinforced,"  2d  Edition,  p.  285. 


NEED   AND   FUNCTION   OF   WATERPROOFING  13 


EFFECT  OF  UNEVEN  SETTLEMENT  ON  MACONRY 

A  fifth  important  destroying  agency  to  consider  in  concrete  con- 
struction is  uneven  settlement.  An  inequality  of  bearing  power  will 
cause  uneven  settlement  in  a  structure.  Only  the  most  careful  de- 
signer can  minimize  and  perhaps  eliminate  settlement,  which  some- 
times causes  unsightly  cracks,  and,  of  course,  reduces  the  imperme- 
ability of  the  structure.  Retaining  walls  are  particularly  subject 
to  stresses  of  this  character.  Bridge  abutments  and  building  foun- 
dations sometimes  suffer  a  good  deal  from  this  cause.  When  to  this 
is  added  the  vibration  in  each,  due  to  traffic  or  the  operation  of 
machinery,  the  injuries  are  enhanced  in  a  manner  that  invites  further 
damage  when  water  enters  the  cracks. 

Where  masonry  walls  support  backfill  behind  them  and  tracks 
above  them,  settlement  may  occur  due  to  pounding  of  trains  on 
the  tracks.  Or,  if  drainage  behind  the  walls  is,  or  becomes,  inade- 
quate for  any  unforeseen  reason  (due  to  clogging  of  weep  holes,  for 
instance),  the  earth,  underneath  the  foundation  may  be  undermined, 
causing  more  or  less  settlement  with  consequent  cracking  and  the 
percolation  of  water.  Concrete  reservoirs  often  develop  cracks 
from  this  cause,  and  in  spite  of  their  eventual  silting-up  often  con- 
tinue to  be  troublesome  until  properly  waterproofed.  In  fact,  it  most 
generally  happens  that  settlement  cracks  are  too  large  to  be  closed 
up  by  silting,  or  there  may  be  no  silt  to  depend  on,  as  when  building 
in  rocky  strata.  But  even  where  silt  is  abundant  and  is  depended 
upon  to  close  up  any  cracks,  it  always  takes  time,  invariably  defaces 
the  structure,  and  the  cracks  may  reopen  by  further  settlement. 
Consequently,  nothing  remains  to  be  done  but  to  waterproof  the 
structure,  in  a  manner  that  will  minimize  or  vitiate  the  effects  of 
this  agent. 

Hygienic  Need  of  Waterproofing.  The  above  considerations 
undoubtedly  establish  the  fact  that  the  ill  effects  of  the  inherent 
porosity  of  concrete  and  the  perviousness  of  general  masonry  should 
be  eliminated  as  far  as  possible  as  a  matter  of  economy  and  safety. 
And,  incidentally  with  the  exclusion  or  repulsion  of  water  (which 
action  depends  on  the  system  of  waterproofing  employed)  from  a 
concrete  structure,  that  is,  with  a  dampproof  and  waterproof 
condition  of  a  structure,  follow  other  results  and  benefits  that  have 
both  an  aesthetic  and  hygienic  effect  which  can  ill  afford  to  be  over- 
looked. Concrete  construction  which  proceeds  with  the  idea  of 
permanency  should  embody  the  co-ordinate  functions  of  damp- 
proofness  and  waterproofness  and  uniform  surfaces,  free  from 


14 


WATERPROOFING  ENGINEERING 


I 

bC 

.S 


NEED  AND  FUNCTION  OF  WATERPROOFING       15 

unsightly  blotches  and  discoloration  by  efflorescence.  (See  Fig.  2.) 
The  latter  defect  in  concrete  and  brick  masonry  is  mainly  due  to  the 
absorption  of  atmospheric  moisture,  which  dissolves  the  salts  of  soda, 
potash,  magnesia,  etc.,  present  in  the  cement  and,  on  evaporating, 
deposits  them  on  the  surface.  But  in  many  instances  rain  or 
ground  water  from  behind  walls  or  other  structures  percolates 
through  the  mortar  or  expansion  joints,  day's-work  planes,  cracks, 
or  through  the  very  body  of  the  masonry,  carrying  with  it  also  various 
oxides  which  leave  rusty  looking  streaks  or  white  and  yellow  patches 
on  the  face  of  the  masonry  that  often  makes  an  eyesore  of  an  othei- 


FIG.  3. — Evidence  of  Exudation  of  Lime  Salts  through  Wall  Unprotected  by 
Waterproofing  or  Dampproofing. 

wise  beautiful  engineering  structure.  (See  Fig.  3.)  This  condition 
is  true  of  masonry  both  above  and  below  ground,  although  in  the 
latter  case  it  is  usually  neglected.  Where  only  this  condition  is 
to  be  prevented,  the  incorporation  of  a  bona-fide  integral  compound 
is  the  most  efficient  means  of  accomplishing  the  desired  end.  Where, 
however,  cracks  are  inevitable,  only  a  membraneous  system  of 
waterproofing  can.  overcome  this  defect. 

In  building  construction,  the  absorption  and  retention  of  moisture 
in  walls  above  ground,  and  moisture  and  water  in  cellar  and  founda- 
tion walls  and  floors  below  ground,  cause  dampness  which  is  harm- 


16  WATERPROOFING  ENGINEERING 

ful  to  health.  Hence  dampproofing,  particularly  in  exposed  build- 
ings, assumes  grave  importance,  and  further  emphasizes  the  n3ed  of 
waterproofing,  because  this  always  acts  as  an  effective  dampproofing; 
that  is,  any  structure  that  has  been  waterproofed  has  necessarily 
been  dampproofed.  There  are  conditions,  however,  where  damp- 
proofing  alone  is  necessary  or  possible,  as  for  instance,  exposed  walls 
of  buildings.  These  are  usually  and  successfully  coated  with  a  bitu- 
minous compound  or  covered  with  a  thin  (J  inch  to  J  inch)  layer 
of  plaster  or  cement  mortar.  Sometimes  a  waterproofed  cement 
mortar  coat  is  applied  an  inch  or  less  in  thickness  for  this  purpose, 
and  if  the  work  is  carefully  done  so  that  no  separating  plane  is  left 
or  peeling  follows,  proves  an  efficient  dampproofing  medium. 

From  the  foregoing  it  may  be  concluded  that  waterproofing 
requires  as  careful  consideration  in  engineering  work  as  fireproofing 
does  in  building  work.  With  so  many  deleterious  agents  constantly 
at  work,  not  only  on  concrete  but  on  all  masonry,  the  imperative 
need  of  protecting  all  manner  of  structures  against  them,  or  against 
their  effects,  becomes  apparent.  The  form  of  this  protection  is 
known  by  the  broad  name  of  waterproofing,  and  the  art  of  applying 
it  as  waterproofing  engineering.  To  dampproof  is  to  make  a  struc- 
ture impervious  to  moisture.  To  waterproof  is  to  render  a  structure 
impervious  to  moisture  and  water.  To  accomplish  this  is  to  preserve 
and  lengthen  the  life  of  a  structure,  and  this  in  turn  tends  towards 
economy,  which  is  an  equally  important  consideration  to  the  archi- 
tect or  engineer  in  design  and  construction  as  to  the  builder  or  owner 
of  a  structure. 


CHAPTER    II 
SYSTEMS   OF  WATERPROOFING 

Progress  of  the  Art  of  Waterproofing.  The  progress  that  the  art  of 
waterproofing  has  made  since  it  began  to  receive  serious  consideration 
Is  quite  notable.  It  is  difficult  to  affix  any  definite  date  to  the  adop- 
tion of  scientific  waterproofing,  but  even  as  late  as  1870  waterproofing 
engineering,  in  the  broad  sense  we  are  now  considering  it,  was  more 
speculative  than  experimental.  About  this  time  the  "  Sylvester 
Process  "  of  waterproofing  (originated  in  England)  came  into  vogur 
among  American  engineers,  and  while  it  still  is  sometimes  employed, 
it  has,  in  the  main,  been  superseded  by  better  methods  and  materials. 
Not  that  asphalt 'was  unused  prior  to  this  date  for  waterproofing 
purposes,  but  there  seems  to  have  been  no  certainty  of  results  con- 
nected with  its  use. 

Since  this  period  and  up  to  comparatively  recent  times  there  were 
developed  four  distinct  systems  of  waterproofing,  namely,  "  Mem- 
brane," "  Mastic/7  "  Surface  Coating,"  and  "  Integral."  In  the 
last  decade,  a  fifth  system — one  that  will  often  obviate  the  need 
of  any  of  the  first  four — has  received  wide  experimentation  with 
very  good  and  consistent  results.  This  system  is  applicable  only  to 
concrete  structures  and  is  designated  "  Self-densified  Concrete." 
Another  recent  system  of  waterproofing  is  known  as  the  "  Grouting 
Process,"  which  is  especially  applicable  to  subsurface  structures 
such  as  tunnels  and  cutoff  walls  either  in  rock  or  earth.  Both  of 
these  systems  will  be  considered  in  due  order. 

The  modern  systems  of  waterproofing  then,  if  arranged  in  the 
order  of  their  development,  appear  to  be  as  follows: 

(1)  "  Surface  coating."  (4)  "  Integral."  f 

(2)  "Membrane."*  (5)  "  Self-densified  concrete." 

(3)  "Mastic."  (6)  "  Grouting  process." 

*  Mr.  E.  W.  DeKnight  claims  to  have  introduced  this  term  in  1902;  but 
this  term  as  applied  to  waterproofing  has  only  been  used  extensively  in  the  last 
decade 

t  This  term  as  applied  to  waterproofing  was  used  as  far  back  as  1875  but  not 
extensively  until  the  last  decade. 

17 


18  WATERPROOFING  ENGINEERING 

SURFACE  COATING  SYSTEM  OF  WATERPROOFING 

Definition,  Purpose  and  Development.  The  surface  coating 
system  of  waterproofing  refers  to  the  application  of:  (1)  In  imper- 
vious coating  of  plastic  or  liquid  bituminous  materials;  (2)  various 
liquid  hydrocarbons,  and  chemical  salt  solutions  forming,  usually, 
water-insoluble  compounds;  (3)  a  wash  or  plaster  coat  of  neat 
cement  or  cement  mortar,  the  former  varying  in  thickness  from 
-£2  inch  to  -£2  inch,  used  principally  on  brick  walls,  and  the  latter 
from  \  inch  to  2  inches;  both  applied  either  to  an  interior  or 
exterior  surface  of  concrete  or  other  masonry.  The  cement 
mortar  coating,  again,  may  be  composed  of:  (a)  cement,  sand 
and  water  mixed  in  any  efficient  proportion  that  will  produce 
a  dense  and  impervious  coating;  (6)  cement,  sand,  water  and  a  pow- 
der, paste  or  liquid  waterproofing  compound  (usually  of  a  proprietary 
nature)  which  is  mixed  in  specified  proportions  for  the  purpose  of 
producing  similar  or  more  impervious  coatings. 

The  surface  coating  system  of  waterproofing  is  adapted  to  water- 
proof structures  either  during  construction  or  after  erection.  It  is 
applicable  either  to  the  external  or  internal  surfaces  of  the  structure, 
depending  on  the  physical  condition  of  the  surface  to  receive  the 
waterproof  coating,  the  water  pressure  behind  the  surface,  the  kind 
of  material  used  and  the  thickness  of  the  coating  to  be  applied.  This 
method  is  comparatively  cheap  and  has  a  wide  application  in  spite 
of  the  few  materials  (other  than  proprietary  ones)  adapted  for  such 
coatings. 

Amongst  the  oldest  preserving  processes  in  construction  work 
are  plastering  and  painting.  Since  paint  forms  an  impervious  coat- 
ing easily  and  cheaply  applied,  it  was  utilized  not  only  for  decorative, 
but  also  for  dampproofing  purposes.  It  was  a  matter  of  general 
knowledge  that  linseed  oil  paints  and  varnishes,  besides  serving 
other  obvious  purposes,  were  also  a  dampproofing  medium;  that 
lime  plaster  and  cement  mortar,  especially  the  latter,  applied  in 
comparatively  thin  coats,  performed  the  same  function.  Hence  the 
next  step  in  the  development  of  this  system  of  waterproofing  was  to 
apply  a  coat  of  bituminous  paint  or  a  mortar  coat,  thick  and  dense 
enough  for  each  material  to  act  also  as  waterproofing.  Eventually 
there  came  into  use  proprietary  waterproofing  compounds  employed 
directly  as  surface  coatings  or  incorporated  in  the  plaster  or  mortar 
coat  to  increase  its  imperviousness. 

The  surface  coating  system  of  waterproofing  is  in  common  prac- 
tice to-day,  especially  the  mortar  surface  coat,  because  with  it  the 


SYSTEMS  OF  WATERPROOFING 


19 


engineer  encounters  the  least  difficulties.  The  invention  of  the 
"  cement  gun  "  has  made  this  possible  more  so  than  any  improvement 
in  the  grading  or  proportioning  of  the  ingredients  for  producing 
impervious  mortar.  The  history  of  this  invention  is  rather  inter- 
esting. About  1895  Mr.  C.  F.  Akeley,  a  taxidermist  of  Chicago, 
invented  the  cement  gun  for  the  special  purpose  of  coating  the 
framework  of  a  dilapitated  house  with  morta^  to  save  it  from  de- 
struction. This  proved  so  successful  that  he  coated  other  frame 
buildings  by  the  same  means.  In  1911  engineers  in  the  United 
States  service  in  the  Philippines  experimented  with  a  similar  machine 
until  they  perfected  it,  and  then  used  it  quite  extensively.  Since 
then  the  cement  gun  has  come  in  modified  and  improved  form, 
into  quite  general  use. 


FIG.  4. — Applying  Plaster  Coat  Over  Bituminous  Dampproofing  Coat. 

Methods  of  Applying  Surface  Coatings.  There  are  three  com- 
mon methods  of  applying  impervious  coatings:  (1)  by  brush,  (2) 
by  trowel,  (3)  by  machine.  All  liquid  compounds  are  applied  with 
a  brush  (see  Fig.  4) ,  or  paint-spraying  machine,  both  processes  being 
done  in  the  same  manner  that  paints  are  applied.  When  thus  applied, 
the  compound  either  forms  a  film  on  the  surface  or  penetrates  the 
surface  of  the  mortar  or  concrete,  and  by  capillary  action  is  drawn 
further  in  to  a  depth  varying  between  J  and  J  inch  (see  Fig.  5), 
depending  on  the  solvent,  porosity  of  the  surface  and  density  of  the 
mortar  or  concrete.  As  a  plaster  coat,  the  given  waterproofing 
material  is  applied  with  a  trowel  by  hand  (see  Fig.  4) .  In  this  proc- 
ess pressure  and  uniform  motion  are  essential,  but  most  essential 
is  the  continuity  of  the  coating.  As  a  mortar  coat  it  may  be  applied 


20 


WATERPROOFING  ENGINEERING 


either  with  a  trowel  or  with  the  cement  gun.  When  the  plaster, 
neat  cement,  or  mortar  surface  coatings  are  applied  with  a  trowel, 
as  on  the  back  of  a  retaining  wall,  the  outside  of  a  brick  sewer  or 
manhole,  the  inner  face  of  a  tunnel  or  swimming  pool,  they  should 
be  finished  off  to  bear  a  smooth  or  granolithic  face.  The  granolithic 
surface  on  these  coatings,  produced  only  by  careful  troweling, 
materially  increases  their  imperviousness.  The  coatings  should 
not  be  made  too  thin,  as  peeling,  blistering,  and  cracking  inevitably 
follow,  especially  if  used  where  they  are  subject  to  atmospheric 
changes. 

When  mortar  is  applied  with  the  cement  gun,  the  coat  can  be 
made  a  very  efficient  waterproofing  medium,  provided  the  materials 
are  properly  used  and  proportioned.  In  no  case  should  a  leaner 
mixture  than  1  :  3  be  used  and  the  best  results  will  follow  the  use  of 


FIG.  5. — Ideal  Penetration  of  Surface  Coating. 


a  clean,  somewhat  moist  and  coarse,  but  graded  sand  in  the  mixture. 
In  operating  the  cement  gun  (see  Fig.  6)  the  dry  materials  are  forced 
through  a  hose  by  means  of  compressed  air,  hydrated  at  the  nozzle, 
and  applied  with  any  desired  velocity.  This  velocity  of  approach 
of  the  mixture  produces  a  considerable  rebound  of  the  sand,  which 
is  wasted;  this  leaves,  however,  the  adhering  mixture  richer  in 
cement.  The  combination  of  cement,  sand  and  water  which  pro- 
duces the  plastic  material,  takes  place  in  transit,  i.e.,  the  hydra tion 
takes  place  immediately  before  and  during  the  placement;  the 
chemical  combination  or  initial  set  of  the  cement  takes  place  in  its 
final  resting  place.  If  the  surface  is  floated  immediately  after  placing, 
a  smoother  finish  is  obtained.  Troweling,  however,  will  not  always 
increase  the  imperviousness  of  the  mortar,  and  may  even  offset  the 
good  effects  of  floating,  hence  it  should  be  practiced  with  great  care 
or  not  at  all.  The  technique  of  cement-gun  applications  requires 
thorough  familiarity  with  the  machine  and  proportioning  of  aggregate 


SYSTEMS  OF  WATERPROOFING  21 

before  any  important  waterproofing  work  can  be  prosecuted  success- 
fully. Chapter  VI  contains  a  more  detailed  description  of  the 
modern  cement  gun. 

Preparation  of  Masonry  Surface  Prior  to  Application  of  Coating. 
Before  applying  any  of  the  dampproof  or  waterproof  coatings,  all 
masonry  surfaces  should  be  prepared  by  chipping  off  all  skins  of 
dried  or  hardened  cement  or  other  material,  so  that  practically  an 
entirely  new  surface  is  produced.  It  is  best  to  do  this  not  more 
than  a  few  days  prior  to  the  application  of  the  coatings.  Chipping 


FIG.  6. — Applying  Mortar  Coat  with  Cement  Gun.     (Operated  with  Power 
from  Automobile  Engine.) 

the  surfaces  will  be  facilitated  and  a  much  better  bond  secured  by  a 
previous  application  of  muriatic  acid  of  about  1  to  10  solution,  the 
strength  of  the  solution  depending  on  the  age  of  the  structure  to 
be  treated.  The  acid  should  remain  on  the  surface  until  it  has 
exhausted  itself.  This  will  require  about  fifteen  minutes.  Then 
a  second  coat,  and  if  necessary  a  third  coat  of  acid  solution  should 
follow  the  first  and  be  brushed  in  with  a  stiff  wire  brush.  When 
sufficient  aggregate  has  been  exposed  and  the  entire  surface  cleaned, 
all  traces  of  the  acid  must  be  removed.  This  is  best  accomplished 
by  a  rigid  application  of  water  from  a  hose  immediately  after  the 


22  WATERPROOFING  ENGINEERING 

acid  treatment  has  reached  a  satisfactory  stage.  This  slushing, 
which  should  be  done  with  perfectly  clean  water,  should  continue 
until  all  the  salts  (formed  by  the  chemical  action  of  the  acid  on  the 
cement)  are  removed  and  the  surface  is  free  from  acid.  All  holes, 
large  or  small,  should  be  plastered  up  independently  of  the  surface 
coating  unless  the  coating  is  a  waterproofed  mortar. 

Application  of  Slush,  Scratch,  and  Finishing  Coats.  If  the  wall 
or  other  surface  is  not  washed  with  acid  it  should  at  least  be  chipped 
and  brushed,  and  just  before  the  mortar  coating  is  to  be  applied, 
the  surface  should  be  thoroughly  drenched  and  soaked  to  its  full 
absorbing  capacity.  Then,  before  the  walls  or  other  surfaces  show 
marked  signs  of  drying,  a  "  slush  coating  "  should  be  applied  over 
the  entire  surface.  To  prepare  this  slush  coat  some  of  the  mixed 
ready-for-use  coating  material  may  be  thinned  with  water  to  the 
consistency  of  cream.  It  is  then  applied  with  a  stiff  brush,  with  a 
scouring  effect,  care  being  exercised  to  fully  cover  the  inner  surfaces 
of  all  crevices  and  holes. 

Before  the  slush  coating  has  dried,  the  first  application  of  the 
regularly  mixed  coating  material  should  be  applied  as  a  scratch  coat, 
from  J  to  J  inch  thick,  and  pressure  brought  on  the  trowel  to  push 
the  coating  on,  and  so  obtain  a  uniformly  thick  layer,  well  bonded. 
The  best  practice  is  to  trowel  the  scratch  coat  to  a  fairly  good  sur- 
face, and  then  to  scratch  criss-cross  over  the  entire  surface  before  it 
hardens.  This  insures  a  better  bond  for  the  finishing  coat. 

Upon  the  scratch  coat,  and  before  its  final  setting,  a  finishing 
coat  of  sufficient  thickness  to  obtain  the  required  thickness  of  mortar 
coat  should  then  be  applied.  If  this  required  thickness  is  more  than 
1J  inches,  the  thickness  of  the  scratch  coat  should  be  increased 
accordingly.  The  finishing  coat,  too,  should  be  pushed  on  hard  and 
uniformly  troweled  and  floated  to  a  true  surface,  free  from  pits, 
pin  holes,  sagging  cracks,  projections  or  other  defects.  The  floating 
of  the  finished  surface  is  best  done  from  the  bottom  of  the  wall  up. 
These  instructions  are  applicable  whether  the  coating  contains  a 
waterproofing  compound  or  not. 

In  general,  also,  the  surface  of  masonry  to  be  waterproofed  by 
the  surface  coating  system  of  waterproofing  should  be  cleared  of 
any  interference  from  timbers  and  temporary  struts,  because  the 
presence  of  such  false  timbering  interferes  with  the  proper  and  con- 
tinuous application  of  the  waterproofing.  If  such  false  timbering 
is  not  readily  removable,  then  the  locations  of  struts  and  posts,  etc., 
resting  on  or  against  the  surface  to  be  waterproofed,  require  very 
careful  workmanship  and  close  inspection  to  insure  the  proper  and 


SYSTEMS  OF  WATERPROOFING  23 

Complete  waterproofing  of  holes  left  by  removal  or  shifting  of  such 
false  work  on  the  completion  of  the  construction  in  hand.  This 
is  especially  true  when  such  timbering  is  situated  in  poorly  illumined 
and  cramped  areas.  A  method  of  overcoming  these  difficulties  is 
explained  in  the  article  on  the  membrane  system  of  waterproofing. 
Other  means  of  procuring  a  continuous  surface  so  as  to  avoid  leaving 
unwaterproofed  areas  will  suggest  themselves  as  the  occasion  arises; 
the  important  point  to  remember  is  that  every  temporarily  unsur- 
faced  spot  constitutes  a  weakness  in  the  waterproofing  system. 

Materials  Used  for  Surface  Coatings.  The  materials  generally 
used  for  surface  coatings  are:  (1)  neat  cement,  cement  mortar, 
and  proprietary  cements,  i.e.,  ordinary  cements  containing  void- 
filling  or  water  repelling  substances;  (2)  finely  powdered  metals,  as, 
for  instance,  powdered  pig  iron;  (3)  mixtures  of  soap  and  alum; 
(4)  paraffin,  either  in  liquid  form,  or  in  solid  form,  but  melted,  or  in 
solution  with  petroleum  oil  or  coal-tar  naphtha;  (5)  patented  bitu- 
minous products,  i.e.,  mixtures  of  asphalt,  linseed  oil  or  wood  oil 
and  resin  with  some  form  of  inert  filler,  as  powdered  or  shredded 
asbestos;  (6)  proprietary  liquid  hydrocarbons,  i.e.,  solutions  of 
paraffin  in  benzine  or  benzol,  or  emulsions  of  petroleum  oil  and  fat 
oil.  Some  of  these  can  be  applied  to  a  wet  or  submerged  surface 
(varieties  of  the  patented  bituminous  products),  but  a  dry  surface  is 
always  preferable.  The  general  properties  of  some  of  these  materials 
are  treated  in  Chapter  V. 

Practical  but  simple  illustrations  of  the  manner  and  method  by 
which  coatings  are  applied  are  shown  in  Figs.  4,  7,  8.  Fig.  4  shows 
a  brick  wall  below  ground  surface,  coated  with  a  liquid  bituminous 
paint  which  in  turn  is  surfaced  with  a  treated  (i.e.,  waterproofed) 
mortar.  This  process  is  most  effective  as  a  dampproofing  rather 
than  as  a  waterproofing.  Fig.  7  shows  a  culvert  arch  waterproofed 
with  a  plastic,  bituminous  compound.  Fig.  8  is  a  cross-section  of  a 
swimming  pool  waterproofed  with  a  cement  mortar  coating.  To 
this  mortar  was  added  a  definite  amount  of  a  proprietary  powdered 
metallic  compound  to  increase  its  imperviousness. 

Application  of  Cement  Mixtures.  In  applying  either  neat  cement 
or  cement  mortar,  the  engineer  is  not  handicapped  by  lack  of  knowl- 
edge of  the  materials  or  results.  The  required  information  is  readily 
obtainable  with  considerable  certainty.  However,  when  patented 
cements  are  used  this  is  not  true  to  the  same  degree.  Experiments 
and  experience  have  proven  the  waterproofing  qualities  of  the  former, 
but  the  same  cannot  be  said  of  the  latter.  In  fact,  in  many  instances 
ordinary  well-made  and  applied  mortar  will  be  more  effective. 


24 


WATERPROOFING  ENGINEERING 


The  United  States  Army  engineers  recommend  the  use  of  sand- 
cement  for  mortar  coatings.*  This  cement  is  sometimes  substituted 
for  the  natural,  but  Portland  cement  has  been  found  to  be  the  best 
to  use  for  waterproofing  purposes.  For  coating  sea  walls  and  other 
marine  constructions,  puzzolan  or  slag  cement  mortar  is  well  adapted. 
For  coating  exterior  concrete  wall  surfaces  and  interior  surfaces  of 
cisterns  or  tanks,  and  especially  any  masonry  below  ground-water 
level,  Portland  cement  mortar  in  proportions  1  :  1  or  1  :  1J  will 
create  watertightness.  The  mortar  should  preferably  be  applied 
against  the  surface  which  is  to  come  in  contact  with  the  water. 


FIG.  7. — Applying  Bituminous  Coat  with  Brush  to  Arch  of  Culvert. 


But  where  a  good  hold  can  be  secured  for  the  mortar  and  if  made 
thicker  than  J  of  an  inch,  it  may  be  applied  to  the  other  side.  In 
Table  XXXII  are  given  suitable  thicknesses  applicable  to  varying 
heads  of  water.  Where  imperviousness  is  desired  both  ways,  both 
sides  should,  of  course,  be  coated.  Increased  watertightness  will  be 
secured  under  all  conditions,  whether  the  mortar  coat  be  applied 
by  hand  or  machine,  by  troweling  the  surface  to  a  granolithic  finish. 
However,  this  granolithic  finish  must  be  produced  with  the  greatest 
care,  otherwise  it  will  vitiate  its  purpose. 

*  Taylor  and  Thompson,  "  Concrete,  Plain  and  Reinforced,"  2d  Edition. 


SYSTEMS  OF  WATERPROOFING 


25 


Use  of  Lean  and  Rich  Mortars.  The  use  of  lean  or  rich  mortar  is 
mainly  dependent  on  the  purpose  each  is  to  be  put  to.  Mortar 
contracts  on  drying  and  expands  on  wetting,  hence  cracking  invari- 
ably results.  This  is  greatly  reduced  by  reducing  the  proportion 
of  cement,  which  alone  is  affected  and  causes  the  cracks.  In  stucco 
work  or  on  other  superstructural  applications  the  leaner  mortar 
is  most  advisable.  The  sand  should  be  graded  so  that  the  pro- 
portion of  medium-sized  grains  is  small,  and  the  coarse  and  fine  grains 
are  about  equally  mixed. 

Experience  shows,  for  instance,  that  a  plain  1  :  3  stucco,  prop- 
erly applied,  remains  free  from  cracks,  but  is  rather  porous.  A  1  :  2 
stucco,  however,  while  less  porous,  is  subject  to  considerable  crack- 
ing, unless  well  protected  during  the  setting  period.  But  such  pro- 
tection (i.e.,  protection  against  freezing,  or  exposure  to  the  sun  and 
quick  drying  out)  besides  being  a  good  deal  neglected,  is  often 
impossible. 


12  Concrete 


FIG.  8. — Swimming  Pool  Waterproofed  with  Waterproof  Mortar  Coat. 

Hence  it  resolves  itself  to  a  question  of  how  to  make  stucco 
mortar  lean  enough  to  avoid  cracks,  yet  dense  enough  to  be  damp- 
proof.  This  difficulty  is  often  overcome  by  the  use  of  a  suitable 
integral  waterproofing  compound,  or  a  surface  coating  material 
which  evaporates  slowly  and  leaves  the  surface  pores  filled. 

Since  the  strength  of  mortar*  here  is  of  least  consideration,  and 
absolute  impermeability  of  the  mortar  of  secondary  consideration, 
(i.e.,  the  mortar  for  stucco  work  need  but  be  made  dampproof)  these 
waterproofing  materials  find  a  very  good  field  of  usefulness.  But 
the  indiscriminate  use  of  such  compounds  as,  for  instance,  soap  and 
alum  washes,  caustic  potash,  stearin  and  resin  compounds,  or 
chloride  of  lime  and  other  metallic  salts,  or,  for  that  matter,  any 
of  the  many  waterproofing  or  dampproofing  compounds,  without 
test  or  careful  investigation  is  unwarranted.  The  architect  who 
specifies  any  of  these  compounds  without  investigating  or  experi- 
menting (and  all  too  many  do  so)  to  ascertain  their  value  for  this 


26  WATERPROOFING  ENGINEERING 

particular  purpose  is  wasting  his  clients'  money  and  hazarding  his 
own  reputation.  The  many  worthless  and  the  few  worth  while 
compounds  on  the  market  make  it  imperative  to  search  most  con- 
scientiously for  a  material  that  will  not  wash  out  after  a  few  rain 
storms;  that  will  not  discolor  or  disintegrate,  or  induce  disintegra- 
tion; that  will  prevent  hair  checks  and  remain  cementitious  while 
creating  imperviousness  in  the  stucco,  and  that  will  not  induce 
peeling  or  blistering  of  the  stucco.  Service  and  practical  tests  are 
the  best,  and  in  fact,  the  only  means  for  determining  the  effectiveness 
of  any  of  these  materials. 

In  connection  with  the  use  of  a  large  proportion  of  cement  in 
mortar  or  excess  cement  in  concrete,  it  must  be  borne  in  mind  that 
the  practice  is  wrought  with  many  dangers  for  vitiating  its  ostensible 
purpose,  i.e.,  increasing  the  density  of  mortar  or  concrete.  For 
underground  construction  this  practice  is  entirely  warranted  and 
efficacious,  but  for  superstructural  work  of  any  sort  this  practice  is 
successful  only  on  the  performance  of  the  work  with  the  most  pains- 
taking precautionary  measures  for  curing,  drying,  and  seasoning  the 
structures. 

Only  a  few  of  the  many  patented  cements  and  bituminous  paints 
on  the  market  for  waterproofing  by  the  surface  coating  system 
possess  the  requisite  properties  for  efficient  usage.  In  general,  these 
properties  are :  (a)  That  absolute  dampproof  ness  or  waterproof  ness 
be  effected  by  their  use;  (6)  reasonable  cheapness;  (c)  applicability; 
(d)  durability.  Experience  and  experiment  have  shown  that  only 
a  very  few  of  these  special  dampproofing  and  waterproofing  com- 
pounds possess  the  same  effectiveness  as  a  moderately  thick  coating 
of  neat  cement  or  cement  mortar,  the  latter  of  a  maximum  thickness 
of  about  2  inches  for  the  most  adverse  conditions. 

Cement  mortar,  as  ordinarily  mixed,  can  be  made  practically 
impervious  by  the  addition  of  alum  and  potash  soap.  One  per  cent 
by  weight  of  powdered  alum  added  to  the  dry  cement  and  sand  and 
thoroughly  mixed,  and  about  1  per  cent  of  any  potash  soap  (ordinary 
soft  soap)  dissolved  in  the  water  used  in  mixing  the  mortar  will  make 
it  remarkably  impermeable,  but  the  results  are  not  lasting.  A  dry 
clay  mixed  with  cement  in  equal  proportions  and  applied  as  a  coat- 
ing is  also  effective  as  a  waterproofing  agent,  provided  any  form  of 
cracking  is  prevented. 

A  surface  coat  of  cement  mortar  of  a  thickness  and  proportion 
best  judged  from  requirements  at  hand,  is  sometimes  used  for 
creating  a  dry  surface  upon  which  to  apply  a  different  system  of 
waterproofing. 


SYSTEMS  OF  WATERPROOFING 


27 


The  impermeability  of  plain  cement  mortar  is  well  shown  in 
Table  III,  which  is  adapted  to  our  purpose  from  the  United^  States 
Bureau  of  Standards,  Technologic  Paper  No.  3. 

TABLE    III.— PERMEABILITY    OF    MORTAR    OF    QUAKING 
CONSISTENCY 


Proportion  by 
Volume  of 
Portland   Cement 
to   Meramic   River 
Sand. 

Ago  in  Weeks 
when  Tested. 

Cubic  Millimeters  of  Water  Passed  per  Minute  per 
Square  Centimeter  of  Surface  Subjected  to  1.4    km. 
(3.1  Ib.)   Hydrostatic  Pressure.* 

Thickness  of  Test  Pieces  in  Inches. 

1 

2 

3 

1  :2 

4 

0 

8 

0 

0 

0 

26 

0 

0 

0 

1  :4 

4 

1.0 

1.0 

0 

8 

0 

0 

0 

26 

0 

0 

0 

1  :6 

4 

31.2 

24.0 

17.0 

8 

.8 

2.0 

5.0 

26 

.      19 

.8 

.5 

1  :8 

4 

149.0 

324.0 

749.0 

8 

90.5 

132.0 

126.0 

26 

9.0 

9.0 

43.0 

*  Average  value  of  three  test  pieces  tested  for  six  hours. 

Application  of  Powdered  Metal.  The  waterproofing  effective- 
ness of  powdered  metal,  such  as  powdered  pig  iron  or  other  iron  oxide 
depends  upon  the  barricading  effect  of  its  increased  bulk  due  to 
corrosion  while  it  is  held  in  suspension  in  the  gaging  water,  which, 
of  course,  permeates  the  mass.  When  mixed  with  the  cement, 
which  is  the  most  usual  way,  the  moist  particles  of  iron  oxidize  and 
expand,  thus  filling  the  voids  in  the  concrete  mass;  or,  when  applied 
to  the  surface  of  concrete,  either  as  a  slush  coat  or  thin  mortar  coat, 
its  action  results  in  the  production  of  a  hard,  dense,  and  impervious 
finish.  The  corrosion  is  often  assisted  by  the  addition,  in  very  small 
quantities,  of  some  oxidizing  agent  such  as  sal-ammoniac  or  sulphur. 
This  same  mixture  is  often  used,  under  various  trade  names,  as  a 
concrete  floor  hardener.  In  fact,  powdered  metal  finds  its  greatest 
usefulness  in  this  field.  When  so  used  it  should  be  floated  on  the 
surface  and  then  finished  off  with  a  trowel.  Success  in  the  Use  of 
this  material  necessitates  the  employment  of  very  careful  and  skillful 


28  WATERPROOFING  ENGINEERING 

labor.  Quantities  and  rules  for  applying  powdered  metal  are  usually 
issued  by  the  manufacturers  of  these  materials,  and  should  be  care- 
fully followed. 

The  Sylvester  Process.  The  use  of  soap  and  alum  solutions  for 
coating  a  masonry  surface  is  known  as  the  Sylvester  Process  of  damp- 
proofing  and  waterproofing.  It  is  applicable  alike  to  concrete  and 
other  masonry.  It  does  not,  however,  form  a  permanent  water- 
proofing, and  is  not  much  used  at  the  present  time.  In  using  these 
materials  the  following  precautions  must  be  observed:  (a)  Each 
should  be  perfectly  dissolved  before  being  applied.  (6)  The  masonry 
surface  should  be  dry  and  clean  before  application,  (c)  The  air 
temperature  at  the  time  of  application  should  be  between  50  and  60 
deg.  Fahr.  (10  and  15.5  deg.  Cent.),  (d)  The  soap  solution  should 
be  boiling  hot  and  applied  first,  using  a  flat  brush  for  this  purpose. 
The  alum  solution  is  then  brushed  on  at  a  temperature  between  60 
and  70  deg.  Fahr.  (15.5  and  21  deg.  Cent.),  thoroughly  covering  the 
first  coat.  An  interval  of  one  day  should  elapse  between  the  appli- 
cation of  each  set  of  coats.  The  number  of  coats  is  dependent 
on  local  conditions,  including  water  pressure  and  exposure  to  the 
elements. 

The  proportion  of  soap  and  alum  giving  the  best  results  is  f  pound 
of  castile  soap  to  1  gallon  of  hot  water;  J  pound  of  common  alum 
to  4  gallons  of  lukewarm  water.  The  action  is  chemical.  The  two 
materials  combine  to  form  a  stearate  of  aluminum,  which  fills  the 
voids  in  the  concrete  and  is  insoluble  in  water.  A  solution  con- 
sisting of  1  pound  of  concentrated  lye,  5  pounds  of  alum,  and  2 
gallons  of  water,  applied  while  the  concrete  is  green  and  until  it 
lathers  freely,  has  been  successfully  used.  A  cheap  and  effective 
substitute  is  a  mixture  of.  1  part  of  aluminum  sulphate  and  3  parts 
of  hard  soap,  by  weight.  This  may  also  be  used  as  an  integral 
compound,  in  proportions  determined  by  experiment,  for  mass 
mortar  or  concrete. 

Application  of  Paraffin.  The  application  of  paraffin  is  universal 
and  adapted  to  all  classes  of  masonry  above  ground.  If  applied 
cold  it  is  specially  treated,  e.g.,  it  is  boiled  to  rid  it  of  water,  the 
presence  of  which  renders  it  difficult  to  apply,  and  dissolved  in  a 
highly  volatile  compound.  Being  an  almost  colorless,  translucent 
liquid,  it  does  not  change  the  color  of  the  surface  to  which  it  is 
applied.  It  is  easily  applied  with  a  stiff  flat  brush,  and  the  best  results 
are  obtained  by  thoroughly  rubbing  it  into  the  surface,  using  three 
coats  if  the  surface  is  rough.  If  the  surface  is  clean  and  smooth, 
two  coats  are  sufficient,  because  the  solvent  has  a  high  penetrating 


SYSTEMS  OF  WATERPROOFING  29 

capacity,  by  which  function  it  leaves  the  pores  filled  with  paraffin 
after  the  volatile  matter  has  evaporated.  Most  paraffin  compounds 
are  prepared  for  use  by  the  manufacturer,  who  usually  issues  direc- 
tions for  their  application,  but  ordinary  commercial  products 
may  be  used.  In  general,  however,  the  following  precautions  should 
be  observed:  (1)  The  surface  treated  should  be  made  smooth 
and  dry,  the  first  by  chipping  all  projections  and  rubbing  with  a 
stiff  wire  brush  if  necessary,  the  second  by  doing  the  work  after  a 
dry  period.  (2)  No  fire  should  be  near  the  material  when  applied, 
because  the  volatile  solvent  is  very  combustible. 

If  the  paraffin  is  to  be  applied  hot,  it  is  merely  melted  and 
thoroughly  rubbed  into  the  surface,  which  has  been  previously  pre- 
pared and  warmed,  to  be  waterproofed.  The  latter  is  most  economic- 
ally done  with  improvised  salamanders,  using  charcoal  as  fuel.  If 
dissolved  in  the  proportion  of  one-third  paraffin  and  two-thirds 
kerosene,  it  remains  soft  longer  and  penetrates  the  stone  further. 
Paraffin  is  the  very  best  waterproofing  material  for  exposed  work 
of  all  kinds,  but  needs  to  be  applied  by  men  experienced  in  this  work. 
With  a  sufficient  penetration,  durability  and  effectiveness  is  assured 
because  of  the  natural  inertness  of  the  paraffin. 

Application  of  Bituminous  Compounds.  There  are  many  bitumi- 
nous paints,  pastes,  and  enamels  offered  by  manufacturers  for  use  in 
the  surface-coating  system  of  waterproofing.  Compounds  of  this 
nature  are  also  used  for  dampproofing.  When  used  for  this  purpose, 
the  film  or  coat  is  usually  applied  somewhat  thinner  than  for  water- 
proofing. For  the  latter  purpose,  the  film  or  coat  does  not  exceed 
J  inch,  except  when  the  material  is  a  bituminous  mastic,  in  which 
case  it  is  applied  in  thicker  form.  If  employed  as  dampproofing  for 
exposed  walls  of  buildings  or  other  superstructures,  these  bituminous 
compounds  are  usually  applied  on  the  interior  or  between  wall  sur- 
faces. As  waterproofing,  these  compounds  are  applied  either  on  the 
exterior  or  interior  surfaces  of  underground  works,  depending  on 
conditions.  In  structures  already  erected  some  of  these  compounds 
are  well  adapted  to  remedy  leaky  conditions  because  they  can 
be  applied  on  the  inside  and  sometimes  to  a  moist  surface. 
This  obviates  the  expense  of  excavating  around  the  foundation. 
Allowing  bituminous  waterproofing  materials  to  remain  in  direct 
contact  with  earth  or  other  backfill,  i.  e.,  unprotected,  is  poor  practice 
because  the  acids  or  alkalies  present  in  the  backfill  will  eventually 
destroy  such  materials.  Bituminous  coatings  are  sometimes  applied 
to  the  inner  surface  of  foundation  walls  and  tunnels  even  where  a 
water  pressure  exists,  but  they  are  not  dependable  to  withstand 


30  WATERPROOFING  ENGINEERING 

this  condition  unless  backed  up  with  an  inch  or  two,  or  more,  of 
cement  mortar  or  concrete,  and  the  work  done  with  care. 

A  priming  coat  should  always  be  used  before  applying  liquid 
bituminous  surface  coatings  to  waterproof  a  structure,  and  in  this 
connection  field  engineers  and  inspectors  will  do  well  to  guard  against 
the  following  practices:  (1)  Failure  to  apply  a  continuous  priming 
coat;  (2)  the  use  of  a  viscous  material  as  a  priming  coat.  On  cer- 
tain construction  work,  especially  municipal  work,  it  is  often  to  the 
advantage  of  the  manufacturer  or  his  agent  to  supply  material  of 
the  same  consistency  for  the  priming  coat  as  for  the  other  coats, 
because  very  much  more  of  it  is  required  for  the  first  than  for  the 
succeeding  coats  on  account  of  the  usual  roughness  of  the  surface. 
The  waste  of  material,  however,  is  the  least  objectionable  in  this 
case.  The  serious  nature  of  such  practice  lies  in  the  failure  to  utilize 
the  priming  coat  for  what  it  was  intended  to  accomplish,  namely, 
to  enter  the  surface  pores  of  the  concrete  or  other  masonry,  to  find 
every  little  depression  or  small  hole  and  coat  it,  and  to  assure  the 
adhesion  of  the  coats  which  follow.  These  objects  are  not  well 
accomplished  by  using  a  viscous  material  for  a  priming  coat.  The 
right  consistency  of  a  priming  coat  is  one  as  liquid  as  water  or  milk, 
in  which  state  it  can  penetrate  deeper  below  the  surface. 

The  composition  of  most  surface  coating  compounds  is  kept 
secret  by  the  manufacturer,  and  the  only  real  safeguard  one  has  in 
purchasing  them  discriminately  is  to  observe  the  results  on  structures 
already  waterproofed  with  any  of  these  products.  In  general,  the 
following  precautions  should  be  observed  when  buying  and  applying 
such  materials:  (1)  Chemical  test  on  a  representative  sample  of 
the  material  should  show  (a)  preponderance  of  bitumen,  (6)  resistance 
to  acids  and  alkalies,  (c)  strong  adhesion  to  concrete  or  other  ma- 
sonry, (d)  toughness  at  low  temperatures.  (2)  Results  of  tests  on 
representative  specimen  should  be  checked  with  material  as  received 
and  then  applied  according  to  the  manufacturer's  directions.  (3) 
The  surface  to  be  waterproofed  must  be  made  clean  and  dry, 
applying  not  less  than  two  coats;  the  first  coat,  usually  a  primer 
(that  is,  the  same  material,  or  ordinary  asphalt  or  tar,  thinned  to  a 
more  liquid  consistency)  is  allowed  to  become  dry  or  nearly  so, 
before  the  second  is  applied.  (4)  Great  care  is  required  (a)  to 
obtain  a  continuous  film  of  coating,  (6)  to  fill  all  corners,  recesses  and 
depressions,  (c)  to  leave  the  final  surface  roughened,  yet  coated, 
if  a  plaster  or  mortar  coat  is  to  be  applied  directly  on  the  film,  (d) 
not  to  injure  the  film  in  applying  these  coats,  and  (e)  not  to  expose 
the  applied  material  unduly. 


SYSTEMS  OF   WATERPROOFING  31 

Straight-run  coal-tar  products  are  often  and  successfully  used 
in  the  surface-coating  system  of  waterproofing.  For  example,  in 
protecting  abutments  and  retaining  walls  from  disintegration  due 
to  their  natural  permeability,  various  dampproofing  bitumens  are 
successfully  and  cheaply  made  and  applied,  of  common  creosote  oil 
and  coal-tar  pitch.  The  creosote  oil  is  applied  first  and  penetrates 
the  wall  to  a  degree  depending  on  its  quality  and  the  density  of  the 
masonry,  and  this  is  followed  by  at  least  two  moppings  of  the  coal- 
tar  pitch.  In  some  instances  where  the  concrete  is  very  porous,  a 
third  and  fourth  mopping  may  be  required  in  order  that  the  entire 
surface  may  be  well  covered.  Dull  spots  on  the  surface  are  evi- 
dence that  the  pitch  has  only  penetrated  into  the  pores  of  the  con- 
crete but  the  outer  surface  is  not  completely  coated.  A  mixture 
of  coal-tar  and  powdered  slate  of  the  consistency  of  molasses  is  often 
used  for  similar  purposes.  Occasionally,  a  2  or  3-ply  felt-  and  pitch- 
membrane  is  applied  to  such  structures. 

Instead  of  the  tar  products,  refined  asphalts  of  good  grade  may 
be  also  used.  Where  a  first  or  priming  coat  is  required,  and  it  is 
practically  always  advisable  to  apply  one,  this  usually  consists  of 
asphalt  diluted  in  naphtha  or  gasolene.  Of  course,  both  the  pitch 
and  asphalt  must  be  of  a  consistency  and  melting-point  to  withstand 
the  local  climate  or  special  condition  of  the  work.  Either  of  these 
materials  will  be  benefited  by  a  protective  coat  of  some  form,  especi- 
ally when  this  waterproofing  is  in  the  form  of  a  felt  or  fabric  mem- 
brane. A  bituminous  paste  composed  of  chinawood  oil,  asbestos 
and  pine  tar  is  well  adapted  for  such  and  similar  purposes,  but  its 
consistency  and  application  must  be  carefully  watched.  Coating  the 
surface  with  boiled  linseed  oil  until  the  oil  ceases  to  be  absorbed  is 
another  method  that  has  been  used  with  success.  In  Chapter  IX 
are  to  be  found  various  formulae  of  compounds  usable  for  damp- 
proofing  and  waterproofing  purposes. 


MEMBRANE  SYSTEM  OF  WATERPROOFING 

Definition,  Purpose  and  Development.  The  membrane  system 
of  waterproofing  refers  to :  (1)  a  built-up,  elastic,  continuous  bitumi- 
nous blanket  or  membrane  composed  of  one  or  more  layers  of  water- 
proofing felt  or  fabric  cemented  together  with  asphalt  or  coal-tar 
pitch,  and  which  more  or  less  completely  surrounds  the  structure 
waterproofed;  (2)  metal  linings,  which  usually  also  constitute  an 
integral  part  of  the  structure,  as  in  steel-plate  or  ring  tunnel 


32  WATERPROOFING  ENGINEERING 

tubes*  wherein  the  metal  lining  is  protected  within  and  without  by 
masonry.  (3)  Any  method  or  material  which  permits  the  more  or  less 
complete  enveloping  of  a  structure  to  prevent  the  passage  of  water 
through  its  exterior  parts,  but  which  is  itself  not  in  direct  contact 
with  the  water,  that  is,  which  is  itself  protected  by  some  other  cover- 
ing. Such  protective  covering  may  be  of  concrete,  vitrified  hollow 
tile,  or  brick  in  cement  mortar  and  sometimes  a  layer  of  mastic. 

The  purpose  of  the  membrane  system  of  waterproofing  is  princi- 
pally to  waterproof  structures  in  course  of  erection,  particularly  those 
below  ground  surface,  such  as  subways,  tunnels  and  building  founda- 
tions; but  it  applies  equally  well  to  retaining  walls,  arches,  reser- 
voirs, etc.  It  is  not  so  well  adapted  to  the  waterproofing  of  structures 
already  erected  or  to  remedy  leaky  conditions  developing  subsequent 
to  erection,  owing  to  the  fact  that  the  membrane  must  be  applied 
to  the  outside  of  the  structure,  thereby  usually  necessitating  con- 
siderable excavation. 

In  the  very  earliest  times,  asphalt  was  used  simply  as  a  surface 
coating,  that  is,  to  serve  as  dampproofing.  In  this  condition  it  was 
not  well  adapted  to  resist  water  pressure,  even  when  placed  between 
two  masonry  surfaces.  To  overcome  this  defect,  fibrous  paper  was 
introduced  between  these  surfaces,  with  a  coating  of  bitumen  on 
either  side.  For  greater  water  pressures,  the  number  of  plies  of 
paper  was  increased,  each  being  coated  with  bitumen  as  applied. 
Paper  was  gradually  superseded  by  waterproofing  felt;  this  was 
largely  composed  of  rag  and  wool,  or  pulp.  The  wool  variety  of 
felt  has  had  until  comparatively  recent  times  a  very  extensive  use, 
but  because  of  the  unreliable  quality  of  wool  purchasable  now,  and 
to  an  extent,  its  high  cost,  rag  felt  and  pulp  felt  are  now  more  com- 
monly used.  These  felts  are  now  in  sharp  competition  with  cotton 
and  jute  fabric.  Commercially,  refined  asphalt  and  coal-tar  pitch 
have  been  used  for  a  long  time  in  connection  with  the  treatment  of 
paper,  felt,  jute  and  cotton  fabric,  and  also  as  a  binder  for  forming 
waterproofing  membranes  of  these  materials.  Now  there  is  some- 
times incorporated  in  these  bitumens  mineral  fillers,  such  as  shredded 
asbestos  for  instance,  for  the  purpose  of  increasing  their  plas- 
ticity and  substantiality 

Applying  the  felt  or  fabric  membrane  to  a  structure  calls  for 
certain  precautions  which  can  ill  afford  to  be  neglected.  These  pre- 

*  Metal  linings  or  castings  may  be  used  anywhere,  but  especially  where 
great  stresses  are  anticipated  or  where  it  is  practically  impossible  to  apply  the 
ordinary  membrane.  This  type  of  construction,  however,  requires  special 
design  for  each  case, 


SYSTEMS  OF  WATERPROOFING  33 

cautions  are  embodied  in  three  fundamental  requirements  to  be  care- 
jfully  observed  in  order  to  insure  good  waterproofing  by  the  membrane 
system.  These  are  (1)  surface  preparation;  (2)  continuity  of 
membrane;  (3)  protection  of  membrane. 

Surface  Preparation  Prior  to  Application  of  Membrane.  It  is 
impossible  to  make  a  bituminous  sheet  adhere  properly  to  a  wet  or 
rough  masonry  surface,  but  it  is  advisable  to  make  it  adhere  to  what- 
ever surface  it  is  applied.  The  surface  to  be  waterproofed  should, 
therefore,  be  prepared  by  chipping  all  projections  and  smoothing  off 
with  mortar  and  trowel  all  depressions;  cleaned  by  sweeping  or 
scraping  off  all  foreign  matter  of  whatever  nature ;  dried  (when  water- 
proofing must  proceed  during  rainy  weather,  or  before  the  concrete 
has  completely  dried  after  setting),  by  heating  the  surface,  if  not 
large,  with  a  gasoline  torch,  by  burning  gasoline  on  the  surface  to 
be  waterproofed,  or  by  employing  salamanders;  or  again,  by  pro- 
viding a  temporary  drainage  system  that  will  keep  the  surface  dry 
during  the  application  of  the  waterproofing.  If  these  measures  are 
impracticable  or  insufficient,  then  one  or  two  plies  of  felt,  with  the 
first  laid  dry,  that  is,  without  a  bituminous  binder  on  the  under  side, 
and  nailed  to  or  against  the  wet  surface,  if  necessary,  will  create  a 
dry  area  for  the  application  of  the  waterproofing  proper.  Where  it 
is  difficult  or  impossible  to  apply  this  dry-ply,  as  on  arches  of  tunnels, 
a  thin  sheet  metal  lining  nailed  to  the  masonry,  or  a  cold  application 
of  asphalt  dissolved  in  naphtha,  or  a  reasonably  thick  plaster  coat 
of  neat  cement  or  mortar,  provides  a  dry  surface  on  which  to  start 
waterproofing.  Of  course  the  concrete  in  all  cases  must  be  thoroughly 
set  before  any  waterproofing  is  applied.  As  an  illustration  of  how 
such  problems  are  met  in  practice,  may  be  cited  the  following 
instance. 

In  building  the  east  face  of  the  south  Manhattan  shafts  of  the 
Pennsylvania  Railroad  tunnels,*  preparations  were  made  to  place 
the  felt  and  coal-tar  pitch  waterproofing  in  the  ordinary  way,  but 
it  soon  became  necessary  to  drain  away  water  that  was  running  down 
over  the  face  of  the  wall  from  the  exposed  rock  above.  To  accom- 
plish this  a  drain  was  constructed  on  the  face  of  the  wall  near  its 
top.  This  consisted  of  a  strip  of  tin  set  in  a  ridge  of  plaster  of  Paris 
stuck  on  the  face  of  the  wall.  The  drain  had  a  slight  grade  down- 
ward. It  answered  the  purpose  very  well,  allowing  the  wall  to 
dry  out  below  the  drain.  This  type  of  drain  was  found  useful  at 
many  points,  because  it  could  be  applied  quickly  and  at  small 
cost. 

*  Transactions,  American  Society  Civil  Engineers,  Vol.  69,  p.  80. 


34  WATERPROOFING  ENGINEERING 

Necessity  of  Continuity  of  Membrane.  Continuity  of  the  mem- 
brane is  more  important  than  the  preparation  of  the  surface  to  be 
waterproofed,  for  it  is  not  always  necessary  to  make  the  membrane 
adhere  to  a  surface  as  long  as  the  sharp  projections  have  been  removed 
and  a  reasonably  smooth  surface  obtained;  but  lack  of  continuity 
creates  a  condition  directly  opposed  to  the  purpose  of  waterproofing; 
for  water  will  find  the  break,  large  or  small,  percolate  through  it, 
and  be  a  source  of  annoyance  at  first  and  danger  at  last. 

The  continuity  of  a  waterproofing  membrane  may  best  be  secured 
by  breaking  joints  systematically  and  leaving  sufficient  lap  to  form 
a  good  connection  with  the  adjoining  section.  In  applying  the 
bituminous  binder  it  is  necessary  to  avoid  blowholes,  "  dry  spots," 
and  other  common  defects.  But  these  dangers  are  partly  obviated 
by  the  very  method  of  building  up  a  membrane  (see  Fig.  14).  In 
using  either  felt,  fabric  or  cotton  drill  for  this  purpose,  such  defects 
will  be  greatly  reduced  by  lightly  pressing  into  the  hot  binder,  which, 
incidentally,  prevents  "  kinks  "  and  also  insures  better  adhesion 
between  successive  plies  as  well  as  to  the  original  surface.  Where 
the  fabric  is  of  the  open  mesh  variety,  the  formation  of  air  pockets 
between  successive  plies  is  automatically  prevented,  and  pressing 
it  into  the  binder  will  insure  the  filling  up  of  all  the  interstices  of  the 
fabric. 

Where  a  connection  is  made  between  a  wall  and  roof  of  a  structure, 
the  lap  should  be  about  1  foot  wide.  The  successive  plies  of  the 
membranous  mat  forming  the  lap  on  the  wall  should  be  interwoven 
with  those  of  the  roof  mat  and  stuck  fast  against  the  side  of  the  wall 
with  binder.  In  joining  the  floor  membrane  with  that  on  the  wall, 
the  latter  should  be  interwoven  as  shown  in  Fig.  9A,  with  the  lap 
ends  of  the  floor  membrane  turned  up  an  amount  depending  upon 
local  conditions,  but  never  less  than  6  inches. 

One  of  the  most  important  matters  in  regard  to  the  continuity 
of  the  waterproofing  membrane,  and  one  requiring  careful  attention, 
is  the  joining  of  new  work  to  old.  The  old  waterproofed  surfaces, 
or  the  old  laps,  should  be  cleaned  of  all  foreign  matter,  and,  where 
necessary,  softened  by  heating,  as  explained  in  "  Surface  Prepara- 
tion." Such  laps  should  receive  a  coat  of  bituminous  material 
before  the  new  strips  of  fabric  are  applied  and  pressed  down 
as  previously  explained.  Where  possible,  a  mesh  joint  should 
be  made  of  the  laps  of  the  old  and  new  fabric  as  the  plies  are  laid  up. 
After  long  exposure  of  a  portion  of  a  membrane  or  its  end  lap,  as 
on  an  uncompleted  portion  of  work,  the  felt  or  fabric  may  have 
deteriorated  or  have  been  torn  off.  It  is  absolutely  necessary  to 


SYSTEMS  OF  WATERPROOFING 


35 


provide  sufficient  lap  width  to  properly  join  the  old  and  new  water- 
proofing; hence  the  safest  expedient  is  to  recoat  the  membrane  with 
a  thick  binder  film  in  the  first  instance,  and  to  cut  back  at  least  6 
inches  of  the  concrete  or  other  masonry  to  secure  sufficient  lap  in 
the  second  instance. 


»:*'  *SSSi^-te?  4-f^\  f^ssKxy^Sfxn: 


DURING  PROCESS  OF  CONSTRUCTION 
A 


WALL  ALREADY   IN   PLACE 

B 


FIG.  9. — Methods  of  Applying  Membrane  Waterproofing  to  Walls  and  Footings. 

Protection  of  Membrane.  The  third  fundamental  requirement 
of  the  membrane  system  of  waterproofing  is  the  protection  of  the 
membrane  during  construction,  but  more  particularly  after.  During 
construction  the  waterproofing  membrane  may  be  injured  by  the 
workmen  carelessly  throwing  about  iron  tools  which  sometimes 
puncture  the  membrane.  The  placing  of  temporary  struts  on  the 
membrane  may  have  a  similar  effect.  Dumping  of  bricks  and  the 
unrestricted  hauling  of  material,  or  walking  on  the  membrane  is 
particularly  harmful  to  its  continuity.  A  waterproofing  membrane 


36  WATERPROOFING  ENGINEERING 

appHed  to  vertical  masonry  tends  to  sag  and  produce  a  rippled 
surface,  especially  in  warm  weather  or  when  a  particularly  soft 
binder  is  used.  In  fact,  no  bituminous  membrane,  no  matter  how 
well  applied  or  what  binder  is  used,  will  stand  up  completely  intact 
without  support  of  some  sort  under  such  conditions. 

After  construction  the  waterproofing  membrane  may  be  injured 
by  the  impact  of  stones  in  the  backfilling  material,  or  by  the  large 
aggregate  in  the  protective  concrete  if  this  is  deposited  from  an 
undue  height;  or  by  bulging  and  running  of  the  bituminous  material 
due  to  heat,  or  cracking  and  chipping  due  to  cold.  Where  there  is 
any  considerable  hydrostatic  pressure  behind  the  membrane  it  may 
be  perforated  in  a  weak  spot,  or  where  a  slight  bulge  or  "  ripple  " 
has  occurred  in  it,  the  added  weight  of  the  water  on  the  bulge  may 
drag  the  membrane  down. 

A  serious  menace  to  bituminous  membranes  surrounding  under- 
ground structures  arises  from  leaks  in  gas  mains  and  sewers  in  city 
streets.  All  gas  mains  collect  a  kind  of  a  pungent  oil  called  gas-drip, 
which  frequently  comes  out  of  leaky  joints  in  the  mains,  saturating 
the  ground  over  considerable  areas.  This  oil  will,  in  a  comparatively 
short  time  destroy  a  portion  of  a  waterproofing  membrane  by  dis- 
solving the  bituminous  binder,  and,  where  felt  is  used,  turn  it  into 
a  soft,  mushy  and  worthless  material.  Then  again  the  membrane 
may  be  attacked  by  lubricating  oil  and  other  solvents  from  leaks  in 
underground  pipes  or  from  machinery,  as  for  example,  where  switch 
pits  for  surface  railroads  are  in  close  proximity  to  the  waterproofing 
of  the  structure. 

Nearly  all  sewers,  besides  carrying  sewage  (which  is  sometimes 
acidulated  and  sometimes  alkaline),  carry  steam  and  other  gases, 
and  where  leaks  occur,  which  happen  quite  often,  the  ground  becomes 
saturated  over  a  considerable  area.  The  deleterious  effect  on  the 
membrane  in  this  instance  is  quite  the  same  as  in  the  case  of  gas-drip 
or  oil,  but  not  so  marked. 

Again,  if  a  membrane  is  injured  in  any  way,  then  the  worst  and 
perhaps  the  only  serious  drawback  of  the  membrane  system  of 
waterproofing  is  encountered.  The  leak  in  the  membrane  is  usually 
inaccessible  from  the  outside  without  costly  excavation,  and  cannot 
be  gotten  at  on  the  inside  except  by  removing  considerable  masonry. 
But  what  is  still  worse,  it  is  almost  impossible  to  tell  where  to  begin 
excavation  or  tearing  out  the  inner  masonry,  due  to  the  fact  that 
water  is  likely  to  travel  a  long  way  between  the  membrane  and  the 
wall  so  that  the  location  of  the  leak  or  leaks  on  the  inside  may  be  as 
much  as  150  feet  from  the  injury  in  the  membrane.  This,  incidentally, 


SYSTEMS  OF  WATERPROOFING 


37 


emphasizes  the  need  for  making  the  membrane  adhere  to  the 
structure. 

To  avoid  possible  injuries  to  the  membrane  during  construction 
due  to  the  causes  mentioned  above,  temporary  protection  should  be 
provided  according  to  circumstances;  for  example,  on  the  floor 
of  a  structure,  by  laying  a  gang-plank  or  enclosing  the  area  with 
an  improvised  board  fence;  or  if  on  a  wall,  by  bracing  strips  of 
wood  against  it,  especially  to  hold  up  the  loose  lap  of  the  membrane 
and  not  allow  it  to  dangle.  Other  expedients  will  suggest  themselves 
as  the  need  arises;  the  important  thing  to  remember  is  that  any 
properly  designed  protection  will  greatly  minimize  the  above  dangers. 

After  construction  there  should  be  placed  on  or  against  the  water- 
proofing a  protective  coat  of  metal  at  the  most  vulnerable  points, 


2  Layers  of  Brick       /  4*  0"  Sewer 


in  Asphalt  Maetic 


FIG.  10. — Roof  of  Ventilating  Chamber  Waterproofed  with  Sheet  Lead  Membrane. 


and  a  protective  coat  of  cement  mortar  or  concrete,  2  to  4  inches 
thick,  over  the  rest  of  the  waterproofing.  Fig.  10  shows  one  way 
of  avoiding  these  dangers,  by  substituting  a  sheet  lead  trough 
for  the  regular  waterproofing  between  a  sewer  and  the  top  of  a  bay 
over  a  subway  ventilating  chamber.  The  protective  concrete 
should  preferably  be  reinforced,  though  this  is  not  always  necessary. 
A  course  or  two  of  bricks,  or  a  wall  of  flat  or  hollow  terra-cotta  tile 
are  also  good  protective  mediums.  On  horizontal  surfaces,  the 
hollow  terra-cotta  tile  should  not  be  used.  The  3-  or  4-inch  concrete 
protective  coat  is  the  best  in  most  instances  because  it  is  the  least 
pervious.  But  in  all  cases  the  protective  medium  should  be  com- 
plete and  cover  every  inch  of  membrane,  and  not  as  shown  in  Fig. 
11  or  Fig.  12A.  Fortunately  engineers  are  fast  learning  the  folly 
of  such  malpractices  as  are  depicted  in  these  illustrations. 


38 


WATERPROOFING  ENGINEERING 


Then  again,  in  protecting  waterproofing  membranes  or  surface 
coatings,  insufficient  consideration  is  often  given  to  the  end  laps. 
Yet  it  is  no  less  important  and  necessary  to  protect  the  ends  than 
the  rest  of  the  membrane  or  surface  coating.  It  should  also  be 
observed  that  in  placing  the  protecting  covering  of  whatever  material, 
it  is  of  primary  importance  not  to  make  water  seams  of  construction 
joints;  in  other  words,  joints  in  protective  coverings  or  layers  should 
be  made  to  offer  the  greatest  resistance  to  the  passage  of  water. 
A  case  in  point  is  well  illustrated  and  self-expkiced  in  Fig.  12 
wherein  the  conditions  referred  to  here  are  manifested  in  a  striking 


m 

Exposed  Membrane 

FIG.  11. — Application  of  Waterproofing  Membrane  with  Insufficient  Protective 

Coating. 


way  on  a  very  important  work.  The  improved  methods  of  pro- 
tecting such  ends  are  simple,  easily  constructed  in  the  field,  and 
cheap  from  every  point  of  view.  A  waterproofing  membrane  of  any 
material  or  a  surface  coating  of  bituminous  material  will  last  very 
much  longer  and  render  better  service  when  properly  protected. 
In  fact,  even  a  1-inch  mortar  coat  is  remarkably  effective  in  this 
direction,  and  is  sometimes  used  even  on  bridge  floors.  But,  in 
general,  for  railroad  bridges,  which  are  subject  to  considerable 
vibration,  a  sheet  mastic  of  about  this  thickness  is  preferable. 

It  is  best  to  place  the  protective  medium  not  later  than  one  or 
two  days  after  the  waterproofing  is  completed.  Where  concrete 
constitutes  the  protective  medium,  it  should  be  poured  from  the 


SYSTEMS  OF  WATERPROOFING  30 

least  height  possible,  as  depicted  in  Fig.  13.  Also,  in  depositing 
heavy  backfill  on  or  against  such  a  comparatively  thin  layer  of 
concrete,  care  and  judgment  must  be  exercised  not  to  break  or 


SHOWING  WRONG  METHODS  OF                             IMPROVED  METHODS  OF 

FINISHING  OFF  WATERPROOFING                PROTECTING  WATERPROOFING  ENDS 

Note  exposed 
lap  of 
membrane  S 

4,     c  Concrete    /Wate^oofing  fN°te  overlaPPin&  of  Protective  concrete  . 

*-    *                 ±              \        \                                                    A  r-  

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brick  in  mastic  surrounded 

Proposed     1     0 

n       Alternate  method  of 

Line  indicated 
on  drawings. 
Line  actually 
worked  to  in  s 
the  field. 
Note  construc- 

L1 \ 

^ 

by  membrane  to  imped 
passage  of  water  wind 
may  enter  construction 
joint  ^ 

Construction  joint.-  - 

7 

position  of   1 
construction' 

J°^i{ 

impeding  water  which 
may  enter  construction 
joints  by  lowering  con- 
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to  the  depth  of  one  brick  . 

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tion  joint. 

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,-  1  Ply  Waterproofing 

\ 

—Concrete 

FIG.  12. — Good  and  Bad  Practice  in  Membrane  and  Brick-in-mastic  Water- 
proofing. 


crush  it.     A  practical  and  instructive  illustration  of  this  danger 
is  given  in  the  following  instance : 

On  the  New  York  Terminal  of  the  Pennsylvania  Railroad  Tunnel 
Extension,  the  protective  cover  over  the  waterproofing  membrane 
was  designed  to  be  of  plain  concrete  from  5  to  6  inches  thick.  As 
long  as  the  backfilling  was  kept  well  back  of  the  completed  work 


40  WATERPROOFING  ENGINEERING 

and  was  stepped  off  in  bench  formation,  the  plain  concrete  cover 
served  its  purpose;  but  in  one  case,  when  the  backfilling  was  advanced 
in  bank  formation  close  upon  the  completed  construction  work, 
the  concrete  cover  broke  and  the  waterproofing  was  damaged, 
requiring  the  removal  of  much  backfilling  to  effect  proper  repairs. 
After  this  occurrence,  the  cover  was  reinforced  with  wire  cloth  and  no 
further  trouble  was  experienced. 

Methods  of  Applying  Membrane  Waterproofing.  In  applying  the 
membrane  to  any  masonry  surface,  the  latter  is  first  mopped  with 
bitumen,  then  the  first  strip  of  felt  or  fabric  is  unrolled  thereon, 
tightly  stretched,  smoothed,  and  pressed  into  the  film  of  bitumen. 
This  strip  is  best  made  continuous  over  the  width  or  length  of  the 


FIG.  13. — Height  from  which  Protective  Concrete  Should  be  Poured  on  Water- 
proofing Membrane. 

structure  where  possible.  In  this  "  continuous  type  "  the  second 
strip  is  laid  to  break  joint  with  the  first  in  a  manner  depending  upon 
the  number  of  plies  usod.  The  various  methods  of  building  up  a 
waterproofing  membrane  are  shown  in  Fig.  14.  The  portion  of  each 
strip  of  fabric  to  be  lapped  should  be  carefully  mopped  as  the  next 
strip  is  laid  over  it.  When  several  strips  have  thus  been  laid,  the 
second  ply  is  similarly  laid,  then  the  third,  fourth,  fifth  and  sixth 
plies,  as  required.  As  each  strip  is  laid  or  applied,  it  is  important 
to  see  that  no  kinks  have  formed  at  the  lap  joints,  for  this  leaves  an 
opening  for  water  to  enter  either  between  or  under  the  membrane. 
The  top  ply  should  always  be  mopped  completely  over  the  entire 
surface,  leaving  no  bare  spots  or  other  imperfections.  See  Table 
XXXII  for  the  number  of  plies  necessary  to  resist  various  heads  of 
water  up  to  42  feet. 


SYSTEMS  OF  WATERPROOFING 


41 


LAYER  TYPE 


CONTINUOUS  TYPE 


One  Ply 


Two  Ply 


Three  Ply 


COURSE  TYPE 


One  Ply 


STAGGERED  TYPE 


Two  Ply 


Six  Ply 

FIG.  14. — Four  Methods  of  Building  up  Waterproofing  Membrane.    Applicable 
to  either  Felt  or  Fabric. 


42 


WATERPROOFING  ENGINEERING 


Making  Membrane  Mats.  Where  it  is  impossible  to  build  up 
the  membrane  directly  on  any  part  of  a  structure,  due  to  physical 
obstructions,  a  mat  of  the  required  number  of  plies  may  be  laid 
up  and  completely  formed  in  any  convenient  place  and  applied  as 
noted  below.  This  mat  is  best  made  as  follows:  The  required 
length  of  felt  or  fabric  is  rolled  out  on  some  clean  surface,  and  the 
top  surface  of  the  strip  mopped;  then  the  second  strip  is  placed 
thereon,  breaking  joint  at  the  one-third,  one-sixth  or  other  portion 
of  the  width  of  the  lower  strip,  depending  upon  the  number  of  plies 
required.  After  mopping  the  second  strip,  the  third  is  applied, 
making  an  equal  lap  with  the  second  strip,  and  so  on.  The  completed 
mat  then  receives  a  top  coat  of  bitumen  and  is  applied  on  the  work 
in  a  manner  similar  to  applying  separate  strips  of  fabric;  that  is, 


• 

Single  3-Ply  Mat  before  Laying     -, 
*   PLAN 

Concrete  Surface* 


SECTION. 


SECTION   A-A 

FIG.  15. — Method  of  Making  Membrane  Mats. 


the  concrete  surface  is  first  mopped  to  receive  the  mat.  Each  mat 
should  lap  over  the  membrane  and  other  mats  already  in  place,  at 
least  4  inches  (see  Fig.  15).  In  no  case  should  the  mats  be  placed 
so  that  the  membrane  formed  has  less  than  the  specified  number  of 
plies  in  the  membrane  proper.  All  exposed  joints  must  receive  a 
final  mopping  and  be  made  as  smooth  as  possible.  When  a  portion 
of  the  structure  being  waterproofed  is  on  a  gradient,  care  should  be 
exercised  in  making  and  applying  the  mats  so  that  the  joints  lap 
each  other  in  the  direction  of  the  down  grade  of  the  structure.  This 
precaution  applies  as  well  to  the  application  of  any  built-up  mem- 
brane, whether  vertically  or  horizontally  applied. 

Connecting  New  and  Old  Membranes.  Joints  form  the  weakest 
part  of  a  membrane;  therefore  too  much  care  cannot  be  exercised 
in  making  a  joint  between  an  old  and  new  membrane  by  a  proper 


SYSTEMS  OF  WATERPROOFING  43 

lap.  Joints  should  be  so  made  as  to  form  as  little  bulge  in  the 
membrane  as  possible,  but  no  butt  joints  should  be  used  on  any  form 
of  waterproofing.  Laps  exposed  for  any  length  of  time  should  be 
carefully  examined  for  any  defects  before  connecting  up,  and  where 
any  defects  or  insufficient  lap  areas  are  found,  the  concrete  or  other 
masonry  should  be  cut  back  sufficiently  to  give  a  proper  lap  between 
the  sound  membrane  in  place  and  the  new  work.  Laps  should  not 
be  less  than  4  inches  wide  for  each  strip  of  fabric,  or  in  any  case  not 
less  than  a  total  of  1  foot. 

Timbers  and  temporary  struts  interfering  with  the  proper  applica- 
tion of  waterproofing  membranes  present  peculiar  difficulties,  and 
their  locations  require  very  careful  workmanship  and  close  inspec- 
tion. The  best  method  to  insure  the  proper  and  complete  water- 
proofing of  the  holes  left  by  the  removal  or  shifting  of  such  false 
timbering,  especially  when  they  are  located  in  poorly  illumined 
and  cramped  areas,  is  as  follows:  All  posts,  struts  or  other  tem- 
porary supports,  whether  on  a  floor  or  roof,  or  against  a  wall,  should 
be  shifted  so  as  to  avoid  breaking  the  continuity  of  the  membrane, 
otherwise  holes  are  left  not  waterproofed.  Where  it  is  impossible 
to  so  shift  these  posts  and  holes  must  be  left  in  the  membrane,  then 
it  is  necessary  to  paint  these  posts  red  or  white,  or  otherwise  to 
distinctly  mark  them,  in  order  that  they  may  be  identified  later 
when  removed  and  the  space  occupied  by  them  waterproofed.  In 
waterproofing  the  space  left  by  the  removal  of  a  post,  or  other  sup- 
port, a  strip  of  fabric  is  cut  to  a  size  not  merely  sufficient  to  com- 
pletely cover  the  space,  but  large  enough  to  lap  2  inches  on  every 
side  of  the  waterproofing  in  place  as  illustrated  in  Fig.  16;  this  total 
area  is  then  mopped  and  successive  plies  of  fabric  are  applied  in  the 
usual  manner.  Each  strip  should  extend  with  a  2-inch  lap  over  the 
one  directly  underneath  it.  The  entire  patch  should  then  be 
thoroughly  and  heavily  coated  with  bitumen.  In  no  case  must  the 
fabric  be  cut  to  fit  only  the  space  occupied  by  the  opening.  Pre- 
pared mats  fitted  into  the  hole  is  also  poor  practice. 

Placing  Membranes  around  Projections  and  in  Vicinity  of  Steam 
Pipes.  Where  pipes  or  rods  project  through  parts  of  a  structure 
that  are  to  receive  the  membrane  waterproofing,  it  is  very  important 
to  make  an  absolutely  watertight  joint  around  these  objects.  These 
joints  are  best  made  as  follows:  As  the  first  ply  of  felt  or  fabric  is 
applied  or  laid  against  the  surface,  a  hole  should  be  cut  in  it  fitting 
snugly  around  the  previously  cleaned  and  mopped  pipe  or  other 
projection.  Then  a  fairly  large  strip  of  felt  or  fabric,  as  the  case 
may  be,  is  placed  completely  around  the  object  so  that  half  adheres 


44 


WATERPROOFING  ENGINEERING 


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SYSTEMS  OF  WATERPROOFING  45 

to  it  and  the  other  half  slitted  radially  adheres  to  the  first  ply  on 
the  wall  Or  other  surface.  The  successive  plies  are  laid  in  the  same 
manner.  A  finishing  ply  is  then  placed  covering  the  slitted  fabric 
and  this  ply  is  cut  only  to  allow  the  pipe  to  pass  through. 

Satisfactory  and  permanent  waterproofing  in  the  vicinity  of 
steam  pipes  is  difficult  to  obtain.  This  may  be  accomplished, 
however,  by  placing  a  strip  of  sheet  lead  of  sufficient  length  and 
width,  and  about  J-inch  thick,  between  the  waterproofing  and  the 
supporting  material  of  the  steam  main.  It  is  understood,  of  course, 
that  the  main  -itself  is  first  adequately  insulated  to  prevent  its  radia- 
ting heat  from  affecting  the  waterproofing.  A  satisfactory  method 
for  insulating  steam  pipes  is  to  surround  them  with  a  blanket  of  ten 
or  twenty  plies  of  untreated  asbestos  felt,  encasing  this  with  large 
semi-sections  of  vitrified  sewer  tiles,  and  packing  the  space  between 
the  two  with  coarse  asbestos  fiber.  The  whole  must  be  well  sup- 
ported on  concrete  or  vitrified  two-  or  four-way  tile  ducts  or  other 
suitable  non-conductive  material,  all  depending  on  the  size  of  the 
steam  main,  location  and  working  conditions. 

The  above  expositions  are  general.  Modifications  will  often  be 
necessary  on  such  structures  as  railroad  bridge  floors,  reservoirs  and 
buildings,  but  the  fundamental  principles  are  the  same.  Hence, 
it  is  not  necessary  to  consider  here  how  each  kind  of  structure  is  to 
be  waterproofed.  The  main  point  to  remember  in  regard  to  all 
types  of  waterproofing  and  all  manner  of  structures  is  to  suit  the 
waterproofing  to  the  structure,  taking  all  local  conditions  in  to  con- 
sideration, including  climate,  purpose  and  type  of  structure.  In 
the  majority  of  cases,  it  may  here  be  noted,  successful  and  durable 
waterproofing  depends  not  only  on  conscientious  labor,  but  more 
particularly  on  expert  supervision. 

Use  of  Special  Membranes.  A  modification  of  the  usual  long- 
strip,  built-up,  elastic  type  of  membrane  consists  of  a  membrane 
made  up  of  small,  square  layers  of  cotton  fabric,*  thoroughly  satu- 
rated and  heavily  coated  on  both  sides  with  a  suitable  bitumen 
and  often  with  a  special,  that  is,  a  proprietary  bituminous  compound. 
The  cotton  fabric  commonly  used  has  a  thread  count  of  66  by  44  per 
square  inch,  weighing  about  4|  ounces  per  square  yard.  When 
treated,  the  fabric  has  an  average  thickness  of  J  inch,  and  weighs 
about  4|  pounds  per  square  yard.  The  operation  of  saturating 
and  coating  the  strips  of  fabric  is  done  in  the  field  immediately 
adjacent  to  the  work  because  the  compound  used  must  possess 
considerable  adhesiveness  so  as  to  stick  well  to  the  applied  surface 

*  Developed  in  1907  by  Oscar  Sheffield,  and  in  practical  use  since  1909. 


46 


WATERPROOFING  ENGINEERING 


and  to  itself  when  lapped  to  form  the  membrane,  hence  it  is  imprac- 
ticable to  handle  the  finished  sheets  between  the  factory  and  the 
field  work. 

The  treated  sheets,  which  are  best  handled  when  about  1  yard 
square,  are  laid  over  the  surface  to  be  waterproofed  with  not  less 
than  a  2-inch  lap.  The  laps  are  then  sealed  with  a  hot  smoothing 
iron  to  insure  perfect  adhesion,  after  which  they  are  recoated  with 
an  additional  layer  of  the  bituminous  compound.  The  membrane 
is  laid  so  as  to  be  continuous  and  unbroken  over  the  entire  area 
waterproofed.  See  Fig.  17.  The  protective  masonry  is  then  applied 
as  on  the  built-up  membrane. 


FIG.  17. — Applying  Treated  Cotton  Fabric. 


Any  good  quality  of  cotton  or  jute  fabric  is  suitable  for  this  type 
of  membrane,  but  only  a  strongly  adhesive,  tough  and  elastic 
bitumen,  and  one  that  will  remain  plastic  at  all  seasons,  can  be  used 
satisfactorily  for  this  purpose.  At  the  present  time  only  one  pro- 
prietary compound  is  extensively  used  for  this  modified  membrane. 
This  compound  consists  of  several  hydrocarbons,  each  possessing 
different  physical  properties  but  mixed  in  proportions  to  secure  the 
desired  consistency. 

Considerations  for  Selecting  Membrane  Reinforcement.  The 
following  question  often  arises  in  waterproofing  design:  What 
reinforcing  material  is  best  adapted  for  the  membrane  system  of 
waterproofing?  In  other  words,  is  treated  felt,  jute  fabric  or  cotton 
drill  to  be  preferred,  and  under  what  conditions  or  for  what  types  of 


SYSTEMS  OF  WATERPROOFING  47 

structures  is  each  best  suited?  This  can  best  be  judged  and  answered 
from  experience.  Felt  was  used  extensively  on  the  old  Manhattan 
subways  in  New  York  City,  in  the  form  of  a  membrane  composed 
of  six  plies  of  felt  and  seven  coatings  of  asphalt,  surrounding  the 
structure  like  an  envelope.  But  it  has  not  given  entire  satisfaction 
apparently  because  this  type  of  membrane  has  insufficient  tensile 
strength,  so  that  when  cracks  developed  in  the  concrete  shell,  it  too 
would  break  somewhere.  Had  this  membrane  been  reinforced 
with  two  or  three  plies  of  jute  or  cotton  fabric,  this  fault  would  not 
be  operative  in  producing  leaks.  Then  again,  the  felt  in  the  mem- 
brane forms  a  stratified  sheet  with  as  many  laminations  as  there  are 
plies  used.  This  creates  many  surfaces  where  water  may  creep 
along  under  certain  conditions,  and  cause  damage.  Its  close  texture 
also  prevents  the  escape  of  entrained  air  during  its  application, 
which  tends  to  create  air  pockets  between  the  plies.  Besides,  there 
is  also  present  the  capillary  action  of  the  felt  fibers,  though  this  is 
not  peculiar  to  felt  alone.  It  has,  however,  a  very  extensive  and 
successful  use  on  all  manner  of  structures  notwithstanding,  and  is 
cheaper  per  unit  of  area  than  either  cotton  or  jute  fabric. 

Jute  fabric,  on  the  other  hand,  such  as  was  used  on  the  new 
Dual  Subways  in  New  York,  also  in  the  form  of  a  membrane  (com- 
posed of  three  to  six  plies  of  fabric  with  from  four  to  seven  coatings 
of  coal-tar  pitch) ,  has  thus  far  given  entire  satisfaction,  and  apparently 
for  the  following  reasons :  The  fabric  being  of  the  open-mesh  variety 
(and  only  such  was  used),  permits  the  bonding  of  successive  plies, 
thus  forming  a  unit-membrane  of  bituminous  material  with  the 
fabric  acting  as  so  much  reinforcement.  The  open  mesh  automati- 
cally prevents  the  formation  of  air  pockets  between  the  plies.  This 
fabric  has  considerable  tensile  strength  and  can  easily  stretch,  with- 
out tearing,  over  ordinary  cracks.  This  allows  the  bitumen  to  heal 
on  favorable  occasions.  There  is  also  somewhat  more  bitumen 
present  in  this  membrane  than  is  ordinarily  present  in  a  felt  mem- 
brane of  an  equal  number  of  plies.  Tests  by  the  author  have  proven 
that  jute  fabric  can  be  thoroughly  saturated  and  coated  with  either 
asphalt  or  coal-tar  pitch,  and  when  so  treated  is  well  preserved 
against  decay.  It  is  from  50  to  100  per  cent  more  expensive  than 
treated  felt. 

On  some  construction  work  raw  burlap  has  been  used  (that  is, 
burlap  not  treated),  but  such  practice  is  open  to  the  following 
objections:  The  hot  bituminous  binder  applied  to  it  in  the  field 
cannot  properly  saturate  it,  neither  is  the  workmanship  in  the  field 
always  conducive  towards  such  accomplishment,  if  that  were  at  all 


48  WATERPROOFING  ENGINEERING 

possible.  And  without  proper  treatment,  the  jute  fabric  will  be 
comparatively  short-lived,  especially  if  exposed  in  the  earth  with 
insufficient  binder;  but  this  is  equally  true  of  the  felts  and  cotton 
fabric. 

The  use  of  treated  cotton  drill  is  undoubtedly  very  good  for 
membrane  waterproofing,  especially  if  it  is  strong  and  well-treated. 
In  fact,  its  use  is  only  prohibitive  on  account  of  its  relatively  high 
cost  when  compared  with  either  treated  felt  or  jute  fabric,  especially 
in  view  of  the  fact  that  the  latter  is  not  less  efficient  in  any  regard. 
All  are  vegetable  products  and  therefore  require  equally  thorough 
saturation.  The  cost  of  the  cotton  drill,  which  is  at  least  double 
that  of  jute  fabric  and  quadruple  that  of  treated  felt,  also  because  a 
more  or  less  laminated  sheet  rather  than  a  reinforced  unit  membrane 
is  formed,  especially  with  the,  ordinary  variety  of  close-woven 
cotton  fabric,  suggests  that  it  be  given  preference  only  after  careful 
economic  consideration.  Saturated  cotton  drill  has  been  used  quite 
extensively  on  the  Boston  subways,  and,  except  for  some  few  leaks 
that  have  developed,  has  given  reasonable  satisfaction.  The  very 
best  and  most  efficient  type  of  membrane  is  one  composed  of  treated 
fabric,  with  small  (in  size  and  number)  open  mesh,  united  with  a 
uniformly  thick  bituminous  binder.  However,  for  ordinary  purposes 
and  for  rigid  structures,  felt  is  entirely  serviceable. 

Storing  and  Unrolling  Felt  and  Fabric.  All  waterproofing  mate- 
rials are  injured  by  improper  storage  and  usage,  particularly  the 
felts  and  fabrics.  Fabric  and  felt  are  delivered  on  the  work  in  rolls 
usually  wound  on  wooden  cores  (for  types  of  cores  see  Fig.  82),  from 
100  to  150  yards  in  length  and  in  varying  widths  from  32  to  50 
inches,  the  42-inch  fabric  and  36-inch  felt  being  most  common.  The 
rolls  should  be  stored  in  a  dry  place,  and  in  warm  weather  the  fabric 
rolls  must  not  be  stood  on  ends.  The  most  satisfactory  way  is  to 
pile  the  rolls  not  more  than  2  or  3  feet  high,  so  as  to  insure  uniform 
bearing  along  their  length,  and  never  to  pile  them  criss-cross.  As 
it  is  possible  to  wind  felt  much  tighter  than  fabric  rolls,  they  may  be 
stored  lying  down  or  standing  up.  In  all  cases,  both  materials 
should  be  protected  from  the  weather  and  from  heat  at  all  times. 

Due  to  improper  storing,  fabric  rolls  become  distorted  and  other- 
wise injured,  and  are  therefore  often  difficult  to  unwind,  resulting 
in  tearing  the  fabric.  Distortion  is  a  defect  which  tends  to  create 
"  waves,"  which  persist  when  the  roll  is  unwound  and  tend  to 
occlude  air  in  the  membrane.  Torn  or  badly  wrinkled  fabric  should 
not  be  used.  The  surface  on  which  the  felt  or  fabric  is  unrolled 
preparatory  to  its  use  in  the  membrane  should  be  clean. 


SYSTEMS  OF  WATERPROOFING  49 

Precautions  When  Heating  Coal-tar  Pitch  and  Asphalt.    Where 

coal-tar  pitch  is  used  as  the  binder  for  membrane  waterproofing,  it 
should  be  heated  gradually  up  to  the  proper  consistency  for  applica- 
tion. This  is  usually  at  a  temperature  between  250  and  350  deg. 
Fahr.  (121  and  149  deg.  Cent.)  for  a  coal-tar  pitch  with  a  melting- 
point  between  115  and  125  deg.  Fahr.  (46  and  51.6  deg.  Cent.). 
Where  asphalt  is  used,  it  too  should  be  heated  gradually,  but  its 
working  temperature  is  higher,  hence  it  may  be  heated  to  a  tem- 
perature between  300  and  350  deg.  Fahr.  (149  and  177  deg.  Cent.). 
Having  reached  the  proper  temperatures,  the  fire  should  be  banked. 
Heating  a  50-gallon  kettle  full  of  coal-tar  pitch  or  asphalt  to  the 
required  temperature  for  application,  by  means  of  a  wood  fire, 
should  take  not  less  than  three  to  four  hours,  for  the  pitch,  while  in 
the  case  of  asphalt  heat  may  be  applied  more  rapidly,  but  should 
take  not  less  than  two  to  three  hours.  A  more  violent  heating  in 
either  case  destroys  these  materials,  especially  the  coal-tar  pitch. 

The  danger  of  overheating,  burning  or  coking  (particularly  the 
pitch)  is  constantly  present,  and  cannot  be  too  strongly  guarded 
against.  One  way  to  prevent  overheating  is  to  stir  the  pitch  occa- 
sionally during  the  melting  process,  and  frequently  after  it  has  melted 
until  it  is  all  used.  Overheating  is  preceded  by  the  rising  of  excessive 
fumes  of  a  light  bluish  tinge.  Burning  is  indicated  by  the  rising  of 
yellow  fumes  from  the  surface  of  the  pitch.  The  odor  or  cackling 
sound  is  not  an  indication  of  the  condition  of  the  bitumen.  Neither 
is  the  practice  of  sticking  a  piece  of  wood  into  the  molten  bitumen  a 
real  indication  of  its  degree  of  heat  or  of  its  condition.  Coking  the 
pitch  is  indicated  by  the  formation  of  a  more  or  less  thin  crust  or 
coating  on  the  bottom  and  sides  of  the  melting  kettle. 

When  by  accident  or  otherwise  the  pitch  is  slightly  burned, 
new  pitch  should  be  mixed  with  it  before  using,  and,  if  badly  burned, 
the  pitch  should  not  be  used  at  all.  It  is  very  essential  to  the  "  life  " 
of  the  pitch  not  to  subject  it  to  prolonged  heating,  even  at  a  low 
temperature,  as  this  drives  off  some  of  the  volatile  oils  which  are  a 
valuable  constituent  of  the  pitch.  The  best  practice  is  to  heat 
only  sufficient  material  for  one  day's  use. 

Asphalt,  though  not  as  readily  affected  by  heat  as  coal-tar  pitch, 
also  requires  in  its  use  the  observance  of  the  above  rules.  The  burnt 
condition  becomes  manifest  by  the  rise  of  blue  fumes  from  the  sur- 
face of  the  asphalt,  and  when  this  happens,  the  fire  should  immediately 
be  extinguished,  and  additional  asphalt  put  into  the  kettle.  If 
the  heat  has  been  excessive  and  protracted,  and  if  the  blue  fumes 
have  been  excessive  and  constant  for  more  than  an  hour,  the  asphalt 


50  WATERPROOFING  ENGINEERING 

should  not  be  used,  because  it  will  undoubtedly  have  changed  or 
lost  some  of  its  properties.  The  effects  of  prolonged  heating  are 
inversely  proportional  to  the  natural  hardness  of  the  bitumen. 

Precautions  should  always  be  taken  against  fire  in  the  heating 
kettles,  and  if  one  starts  water  must  not  be  used  to  extinguish  it. 
As  the  temperature  of  the  pitch  or  asphalt  during  use  is  far  above 
the  boiling-point  of  water,  the  result  of  throwing  on  water  may  be 
serious.  Fires  may  best  be  put  out  by  the  use  of  sand  or  steam. 
As  pitch  and  asphalt  hold  heat  for  a  considerable  time,  the  workmen 
should  be  warned  of  the  danger  of  being  burned  by  these  materials. 

Whenever  it  becomes  necessary  to  transport  bitumen,  as  when  the 
particular  waterproofing  job  is  beyond  a  500-foot  radius  from  the 
location  of  the  heating  kettles  (which  is  quite  common  on  large 
construction  work),  small  portable  kettles  are  used  for  transporting 
the  pitch  or  asphalt.  The  same  precautions  must  be  taken  to  avoid 
burning  and  coking  the  bitumen  in  these  kettles  as  was  previously 
explained  for  the  stationary  heating  kettles.  Where  the  bitumen 
is  carried  in  buckets,  it  is  best  not  to  allow  these  to  stand  more  than  a 
few  minutes  before  using,  as  the  temperature  falls  rapidly  and  the 
material  thickens.  This  condition  prevents  uniform  spreading 
when  the  bitumen  is  mopped  on  the  felt  or  fabric  in  making  the 
membrane. 

Proper  Use  of  Kettles  and  Fuel  when  Heating  Pitch  or  Asphalt. 
Coal-tar  pitch  and  asphalt  have  no  serviceable  affinity  in  water- 
proofing by  the  membrane  or  sheet-mastic  systems.  Their  mixture 
produces  a  product  which  resembles  putty  in  some  of  its  physical 
properties,  except  when  the  amount  present  of  one  or  the  other 
does  not  exceed  5  per  cent.  Hence  the  heating  kettles  should  not 
be  alternated;  i.e.,  kettles  used  for  melting  pitch  should  not  be  used 
for  melting  asphalt  or  making  mastic,  and  vice  versa.  Where  kettles 
must  so  be  used,  it  is  necessary  to  clean  them,  especially  where  either 
material  has  caked  on  the  sides  and  bottom  of  the  kettles,  as  often 
happens.  In  fact  it  is  good  practice  to  thoroughly  clean  the  heating 
and  mastic-mixing  kettles,  portable  kettles  and  pails  not  less  than 
once  a  week  even  though  their  use  was  intermittent.  Kettles 
encrusted  with  bitumen  or  mastic  require  more  fuel  and  time  for 
heating  the  contents.  The  life  of  the  kettle  is  also  reduced  by 
the  presence  of  caked  bitumen  or  mastic. 

The  easiest  obtainable  and  cheapest  fuel  for  heating  kettles  is 
discarded  construction  timber.  Staves  of  asphalt  or  pitch  barrels 
are  objectionable  on  account  of  the  unbearable  volumes  of  smoke 
they  produce.  Much  trouble  and  a  public  nuisance  would  be  avoided 


SYSTEMS  OF  WATERPROOFING  51 

if  there  was  a  law  prohibiting  their  use  in  city  streets.  Cord  wood 
is  the  best  to  use,  because  with  it  a  smouldering  fire  may  be  main- 
tained for  a  long  time.  This  keeps  the  bituminous  material  hot 
without  burning  it. 

Differentiating  between  Coal-tar  Pitch  and  Asphalt  in  the  Field. 
Engineers  unfamiliar  with  bitumen  find  it  difficult  to  distinguish 
between  coal-tar  pitch  and  asphalt,  consequently,  mistakes  some- 
times occur  by  using  one  for  the  other.  Asphalt  may  be  a  product 
of  asphaltic  petroleum,  a  refined  natural  asphalt  or  a  mixture  of 
both.  Coal-tar  pitch  is  a  product  of  the  destructive  distillation 
of  coal  in  the  manufacture  of  coke  or  illuminating  gas.  The  follow- 
ing characteristics  will  aid  in  identifying  each  on  the  work.  Asphalt, 
when  newly  cut,  is  a  bright,  lustrous  black.  It  has  a  pungent  and 
somewhat  rancid  odor  and  taste.  With  the  application  of  heat  of 
equal  intensity,  it  requires  longer  heating  than  coal-tar  pitch  to  be 
brought  to  the  same  liquid  condition  or  equal  temperature.  When 
asphalt  burns  without  flame  its  fumes  are  decidedly  blue.  Coal- 
tar  pitch,  when  newly  cut,  is  somewhat  of  a  dull  black  and  more 
brittle,  as  compared  to  asphalt.  It  has  an  aromatic  taste  and  odor, 
which  is  characteristic  of  pitch  only.  When  coal-tar  pitch  burns 
without  flame,  its  fumes  are  a  dense,  greenish  yellow.  The  safest 
and  most  advisable  thing  to  do  where  both  materials  are  used  on 
the  same  work  is  to  require  the  manufacturers  to  mark  or  label  the 
containers,  so  as  to  make  identification  easy  and  certain. 

Coal-tar  Pitch  Versus  Asphalt  for  Waterproofing.  Whether 
asphalt  or  coal-tar  pitch  is  to  be  preferred  for  membrane  water- 
proofing is  still  a  mooted  question.  No  doubt,  for  certain  special 
uses,  as  for  instance,  where  the  temperature  varies  widely,  the 
asphalt  is  a  preferable  material  because  it  remains  soft  and  workable 
through  wide  temperature  ranges;  if  the  temperature  varies  but 
little,  as  it  often  does  in  underground  work,  straight-run  coal-tar 
pitch  will  give  better  results  on  account  of  its  greater  chemical 
stability.  But  on  general  construction  work,  a  good  quality  of 
either  material  is  equally  serviceable,  the  prevalent  contrary  view 
among  engineers  notwithstanding.  The  author's  experience  has  led 
him  to  the  conclusion  that  certain  brands  of  asphalt  now  on  the 
market  are  even  to  be  preferred  to  some  grades  of  pitch,  for  this 
reason:  The  asphalts  (all  too  few,  though)  as  now  refined,  have 
been  constantly  improving  in  quality,  while  coal-tar  pitch  did  not 
keep  pace.  In  fact,  in  the  last  decade  or  so,  on  account  of  the 
increasing  value  and  importance  of  the  by-products  from  coal  tar, 
and,  due  to  the  keen  competition  in  the  waterproofing  field,  the 


52  WATERPROOFING  ENGINEERING 

quality  of  pitch  has  materially  suffered.  Where  the  quality  of 
pitch  or  asphalt  can  be  controlled  or  ascertained  and  verified,  how- 
ever, their  preference  for  waterproofing  purposes,  assuming  the  con- 
sistency to  be  right  for  the  climate  or  local  requirement,  becomes  a 
question  of  cost.  The  heretofore  superiority  of  pitch  was  due  to  the 
fact  that  asphalt  was  often  produced  as  a  by-product  in  oil  refineries. 
Now  the  practice  is  being  reversed,  hence  the  improved  quality  of 
asphalt  now  available.  But  of  course,  good  straight-run  coal- 
tar  pitch  is  also  available.  The  point  to  remember  is  that  both 
materials,  if  of  good  and  certified  quality,  are  practically  equally 
serviceable,  with  the  exception  noted  above  with  regard  to 
adaptability. 

MASTIC  SYSTEM  OF  WATERPROOFING 

Definition,  Purpose  and  Development.  The  mastic  system  of 
waterproofing  consists  of  (1)  the  application  of  sheet  mastic  (com- 
posed of  asphalt  or  coal-tar  pitch,  sand,  grit  and  cement  or  stone 
dust),  in  the  form  of  a  comparatively  thin  layer,  which  more  or  less 
surrounds  the  structure  to  be  waterproofed;  (2)  a  brick-in-mastic 
or  tile-in-mastic  layer  composed  of  a  course  or  two  of  bricks  or  tile, 
the  joints  being  filled  and  all  faces  covered  with  a  bituminous  mastic, 
the  course  or  courses  covering  the  structure  below  ground- water  level. 

The  sheet  mastic  varies  between  J  inch  and  2  inches  in  thickness; 
the  brick-in-mastic  varies  between  2\  inches  and  8  inches  in  thick- 
ness. The  brick-in-mastic  layer,  being  between  five  and  eight  times 
as  thick  as  a  3-  or  6-ply  membrane,  and  from  four  to  five  times  as 
thick  as  the  sheet  mastic,  is  usually  used  where  great  water  pressure 
exists.  It  is  the  most  dependable  system  of  waterproofing,  though 
also  the  most  expensive.  In  underground  construction  where  head- 
room is  a  factor,  or  in  general  where  insufficient  space  exists  for  the 
application  of  one  or  two  courses  of  brick-in-mastic,  and  where 
sheet  mastic  cannot  be  used,  as  for  instance,  on  sidewalls  of  subsur- 
face structures  a  fabric  membrane  of  from  4  to  8  plies  is  usually  sub- 
stituted. A  felt  membrane  of  an  equal  number  of  plies  should  be 
used  only  when  reinforced  with  1  ply  of  fabric  for  at  least  each  3  plies 
of  felt.  This  precaution  is  not  necessary,  however,  on  very  rigid 
structures,  or  where  expansion  joints  properly  distributed  in  the 
structure,  are  provided. 

Almost  simultaneously  with  the  development  of  the  fabric 
membrane  went  the  development  of  the  sheet  mastic  and  the  brick- 
in-mastic  layers.  Originally,  a  coating  of  mastic  (composed  of  rock 


SYSTEMS  OF  WATERPROOFING  53 

asphalt,  fluxed  to  the  proper  consistency)  between  \  and  \\  inches 
thick,  was  used  mainly  on  horizontal  surfaces.*  In  an  effort  to 
increase  the  depth  and  weight  of  this  coating  for  waterproofing 
purposes,  both  on  horizontal  and  against  vertical  surfaces,  bricks 
or  tiles  were  introduced  between  thinner  layers  of  mastic.  Finally, 
even  the  brick  joints  were  rilled  with  mastic,  resulting  in  the  present 
day  brick-in-mastic  layer  or  envelope.  Where  this  scheme  is  used 
for  waterproofing,  the  materials  are  always  incased  between  concrete 
or  other  masonry  surfaces. 

Applying  Mastic  Waterproofing.  Sheet  mastic  for  waterproofing 
is  mostly  used  on  railroad  bridges  though  it  has  been  employed  on 
underground  construction.  It  is  most  extensively  used  as  a  water- 
proof floor  for  buildings  and  railroad  stations.  Sheet  mastic  is, 
however,  subject  to  abuse  in  its  manufacture  and  application.  For 
instance,  the  quantities  of  the  various  mineral  ingredients  might  be 
poorly  proportioned,  resulting  in  a  mastic  that  is  too  soft  or  too 
hard;  the  quantity  of  bitumen  might  be  insufficient  to  give  good 
cohesiveness  and  elasticity  to  the  mastic.  The  sheet  mastic  might 
be  applied  without  sufficient  precautions  to  prevent  cracks  produced 
by  movement  due  to  temperature  changes  especially  over  large 
areas.  While  the  particular  purpose  in  hand  should  always  be 
considered  in  proportioning  of  the  ingredients  for  making  sheet 
mastic,  still  the  following  general  directions  should  be  adhered 
to:  the  bitumen  and  the  sand  should  each  be  not  less  than  10  per 
cent  of  the  finished  mastic;  the  fine  mineral  dust,  whether  limestone 
dust  or  cement,  should  be  not  less  than  45  per  cent,  and  the  grit 
not  more  than  30  per  cent  of  the  finished  mastic;  the  remaining  5 
per  cent  is  sufficient,  if  carefully  apportioned,  to  take  care  of  any 
special  requirements  of  the  mastic. 

When  serving  only  as  a  waterproofing  medium,  sheet  mastic 
must  be  continuous  over  the  surface  to  which  it  is  applied,  but  its 
abutting  extremities  must  not  be  relied  on  to  make  a  watertight 
connection  with  steel  or  concrete  without  special  provision  being 
made  to  obtain  such  a  condition.  This  may  be  accomplished  by  a 
cove  finish  of  the  ends  or  by  the  use  of  an  adhesive,  plastic  joint  filler. 
Often  sheet  mastic  is  used  in  conjunction  with  other  systems  of  water- 
proofing as,  for  example,  to  cover  a  felt  or  fabric  membrane.  With 
due  precautions  in  its  application,  sheet  mastic  constitutes  a  good 

*  The  use  of  sheet  mastic  (or  sheet  asphalt  as  it  is  popularly  called)  dates  back 
to  1838,  when  it  was  used  to  make  sidewalks  in  Paris.  It  was  made  of  a  bitu- 
minous limestone  from  Seyssel  and  Valde  Travers,  and  since  then  nearly  all 
European  asphalt  paving  has  been  done  with  this  asphaltic  limestone. 


64  WATERPROOFING  ENGINEERING 

waterproofing  medium,  comparable  to  the  brick-in-mastic  system. 
Sheet  mastic  can  be  made  to  withstand  shock  and  vibration  without 
cracking  by  introducing  a  wire  mesh  or  cloth  reinforcement  between 
equal  thicknesses  of  mastic  forming  the  layer.  It  is  much  cheaper 
than  brick-in-mastic,  but  is  not  as  generally  applicable. 

Compared  to  felt  or  fabric  membranes,  the  use  of  brick-in-mastic 
to  waterproof  a  structure  is  more  costly,  and  its  application  often 
more  difficult  and  more  exacting.  The  reason  for  this  is  that  the 
amount  of  labor  necessary  for  preparing  the  mastic  and  laying  the 
courses  to  form  the  envelope  about  the  structure  is  considerably  more, 
as  also  the  quantity  of  material  required  for  equal  areas  to  be  cov- 
ered, than  the  bituminous  membrane.  Figs.  19  and  20  illustrate 
some  of  the  difficulties  contended  with  in  the  application  of  brick- 
in-mastic  to  an  underground  structure,  such  as  a  subway.  The 
section  in  Fig.  18,  representative  of  the  construction  of  the  new 
Dual  Subway  in  New  York  City,  shows  a  typical  arrangement  of  the 
waterproofing  used  on  this  work.  The  brick-in-mastic,  by  its  sub- 
stantial nature,  protects  the  floor  from  percolation  due  to  pressure, 
and  the  bituminous  membrane  protects  the  roof  from  seepage  of 
ground  water. 

The  condition  of  a  structure  to  be  waterproofed  is  not  always 
what  it  should  be  to  receive  the  envelope  of  brick-in-mastic,  hence 
the  structure  must  be  made  adaptable  by  artificial  means  such  as 
smoothing,  drying,  cleaning,  etc.  It  may  not  be  feasible  to  wait 
until  the  concrete  dries  before  applying  the  bri3k-in-mastic,  or  the 
weather  may  make  it  difficult  to  obtain  a  dry  surface.  Where  a 
wet  or  damp  surface  is  unavoidable,  a  ply  of  felt  or  fabric  or  a  mem- 
brane consisting  of  the  two  CD  nbined  should  be  placed  thereon  and 
its  surface  mopped  with  asphalt  if  asphalt  mastic  is  being  used,  or 
with  coal-tar  pitch  is  pitch  mastic  is  used.  Pools  of  water  and  a 
decidedly  wet  concrete  should  first  be  made  reasonably  dry  by  suit- 
able means  before  this  dry  ply  is  laid.  But  no  dependence  for  water- 
proofing is  to  be  placed  on  any  form  of  dry  ply. 

The  waterproofing  mastic  is  usually  brought  to  the  place  of 
application  in  portable  fire  kettles  or  small  pouring  pails.  The 
mastic  should  not  be  allowed  to  stand  in  these  for  more  than  a  few 
minutes  before  using.  Failure  to  observe  this  results  in  a  loss  of  heat 
and  uniformity  of  mixture  due  to  the  quick  settling  of  the  mineral 
aggregate.  In  any  case  the  mastic  should  be  well  stirred  before 
pouring  it  on  the  prepared  surface.  The  carrying  pails  must  be 
scraped  after  each  pouring  to  avoid  caking  of  the  mastic  on  the 
bottom  by  continued  settlement.  The  mastic  should  always  be 


SYSTEMS  OF  WATERPROOFING 


55 


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56  WATERPROOFING  ENGINEERING 

spread  out  to  a  uniform  and  reasonably  thick  film  (about  J  inch) 
before  laying  the  bricks  therein. 

The  bricks,  whose  function  is  to  give  a  substantial  and  thick 
waterproofing  layer,  are  laid  in  the  mastic  so  as  to  be  completely 
surrounded  by  a  film  not  less  than  f-inch  thick.  In  no  case  should 
brick  touch  brick.  A  simple  method  of  obtaining  good  and  com- 
pletely filled  joints  around  the  bricks  is  to  slide  each  brick  into  place, 
somewhat  diagonally  and  with  a  slight  pressure  downward.  This 
will  invariably  bring  the  bed  mastic  up  into  the  joints.  Spalls 
should  not  be  used  under  any  circumstances.  An  effort  should  be 
made  to  use  whole  bricks,  and  bats  but  sparingly.  In  applying 
more  than  one  course  of  brick-in-mastic  it  is  best  to  build  each 
almost  simultaneously,  with  the  lower  course  not  more  thaa  a  few 
feet  in  advance  of  the  upper.  Where  two  courses  are  decided  on 
(in  which  the  bricks  are  ordinarily  placed  on  their  largest  bed)  it 
will  often  be  found  profitable  without  materially  reducing  the-:  effi- 
ciency of  the  envelope  to  build  a  one-course  envelope,  but  with  the 
bricks  laid  on  the  narrow  side.  Ihis  scheme  will  effect  a  saving 
of  22  per  cent  in  material  alone. 

Each  course  of  bricks  is  to  be  covered  with  mastic  so  that  all 
joints  and  hollows  are  filled,  making  the  surface  even.  When 
spreading  the  top  coat  of  mastic,  care  is  to  be  exercised  in  joining 
successive  pourings.  This  top  coat  sometimes  becomes  pitted  or 
perforated  with  numerous  pinholes  exposing  the  bricks.  This  may 
be  largely  overcome  by  increasing  the  amount  of  the  fine  mineral 
aggregate  or  by  adding  a  small  amount  of  asbestos  fiber.  When 
such  a  perforated  condition  is  detected  in  the  finished  envelope 
it  should  be  resurfaced  with  the  pure  bitumen. 

Laying  protective  concrete  should  proceed  immediately  or 
shortly  after  the  surface  mastic  has  cooled.  The  top  or  exposed  film 
of  mastic  covering  the  bricks  must  be  cleaned  in  a  manner  similar 
to  that  previously  described  for  membranes.  Where  temporary 
construction  timber  cannot  be  removed  during  waterproofing  opera- 
tions, these  locations  must  t>e  taken  care  of  similarly  as  described 
under  the  "  Membrane  system."  The  forms  placed  about  post 
holes  to  prevent  the  protective  concrete  from  flowing  into  the  same, 
should  be  made  watertight  to  avoid  coating  the  asphalted  bricks 
as  it  is  difficult  to  remove  the  set  mortar  afterwards.  In 
pouring  the  protective  concrete  on  the  mastic,  it  is  safest  not 
to  exceed  a  drop  of  6  feet  in  height  to  avoid  injuring  the  top 
coating.  The  surface  of  the  protective  concrete  should  be  troweled 
smooth. 


SYSTEMS  OF  WATERPROOFING  57 

Precautions  when  Joining  New  and  Old  Brick-in-Mastic.     The 

ends  of  the  courses  at  the  finish  of  each  day's  work,  or  when  work 
is  temporarily  discontinued,  must  be  well  mopped  with  asphalt  or 
coal-tar  pitch,  depending  on  the  kind  of  mastic  used,  leaving  no 
bricks  uncoated.  To  preserve  the  physical  condition  of  these  ends, 
2-inch  boards  may  be  laid  up  against  them,  especially  where  resump- 
tion of  work  may  be  delayed  for  a  long  time.  In  commencing  the 
new  work,  the  old  surface  should  be  cleaned  and  softened  so  as  to 
properly  join  with  the  new  mastic.  The  use  of  a  gasoline  torch 
or  the  burning  of  some  gasoline  on  the  surface  is  sufficient  to  accom- 
plish this. 

Where  temporary  braces,  posts  and  other  supports  are  used  on  the 
work  and  are  not  moved  to  accommodate  the  brick-in-mastic  layers, 
all  four  sides  of  such  post  holes  should  be  stepped  when  more  than 
one  course  is  used  (see  Fig.  16).  In  waterproofing  these  post  holes 
after  removing  the  posts,  all  surfaces  are  to  be  carefully  cleaned  and 
remopped  with  bitumen.  The  mastic  is  then  poured  on  the  pre- 
pared area  and  the  bricks  embedded  therein  in  the  ordinary  way. 
It  is  advisable  to  dip  these  bricks  in  bitumen  or  mastic  before  laying. 
In  fact,  all  possible  precautions  should  be  taken  to  secure  an  absolutely 
watertight  joint  on  all  kinds  of  patch  work. 

Placing  Mastic  around  Projections  and  in  Vicinity  of  Steam 
Pipes.  If,  through  a  masonry  surface  which  is  to  be  waterproofed 
by  the  application  of  a  layer  of  sheet  mastic  or  brick-in-mastic,  such 
objects  as  pipes  or  rods  project,  careful  workmanship  is  required 
to  make  these  locations  watertight.  Whatever  the  object  be,  that 
part  of  its  surface  which  will  be  included  in  the  waterproofing  layer 
must  be  cleaned  thoroughly.  If  these  objects  project  through  a 
floor  or  roof,  then  it  is  well  to  leave  an  open  ring  about  2  inches  wide, 
completely  around  them,  as  the  course  or  two  of  brick-in-mastic 
is  laid  down.  Then  this  ring  space  is  preferably  filled  with  a  mastic 
of  softer  consistency  than  that  used  ordinarily,  or  with  pure  asphalt. 
Sheet  mastic  may  be  applied  without  this  temporary  space  around 
projecting  objects.  If  objects  project  from  vertical  surfaces,  it  is 
first  of  all  necessary  to  make  the  form  (required  for  placing  brick- 
in-mastic  against  walls)  fit  snugly  around  the  object.  Then  the 
bricks  should  be  so  laid  in  the  mastic  at  these  projections  as  to  leave 
a  space  about  1  inch  wide  around  them,  to  be  filled  by  the  mastic. 
A  better  bond  will  be  secured  between  the  mastic  and  the  pipe,  rod, 
or  other  projecting  objects,  if  these  are  first  swabbed  with  pure 
bitumen.  In  some  instances,  where  the  importance  of  the  work 
warrants  it,  the  efficiency  of  these  connections  will  be  enhanced 


58  WATERPROOFING  ENGINEERING 

by  the  judicious  application  of  waterproofing  felt  or  fabric,  as  for 
instance,  if  the  joints  were  made  as  described  under  "  the  membrane 
system";  then,  by  the  further  filling  of  the  ring  spaces  with 
mastic  or  pure  bitumen,  more  positive  joints  are  secured. 

In  the  event  that  steam  or  hot- water  pipes  or  mains  project 
through  the  masonry,  then  it  is  first  necessary  to  insulate  them  so  as 
to  reduce  the  effect  of  their  radiating  heat  to  a  minimum.  The  usual 
method  for  doing  this  is  also  described  under  "  the  membrane 
system." 

Preparation  of  Wall  Surfaces  for  Brick-in-Mastic.  When  exterior 
waterproofing  is  intended  for  an  underground  structure  running 
through  rock,  an  effort  is  made  while  excavating  to  leave  the  natural 
sides  as  vertical  and  smooth  as  possible.  But  this  is  never  attained. 
Hence  a  sand  wall  of  concrete  is  applied  against  the  natural  rock  to 
supply  a  vertical  and  smooth  surface.  This  acts  as  the  "  armor- 
coat  "  for  either  the  membranous  or  mastic  type  of  waterproofing. 
Excavation  in  earth  requires  the  customary  sheet  piling  and  bracing. 
This  sheet  piling  is  generally  placed  sufficiently  outside  the  neat  line 
to  permit  the  building  of  either  a  one-course  brick  or  terra-cotta 
hollow-tile  wall.  This  wall  then  acts  as  an  "  armor-coat  "  for  the 
waterproofing.  In  some  instances  steel  or  wooden  sheet  piling  is  so 
placed  as  to  preclude  the  possibility  of  building  a  masonry  wall  within 
its  confines,  then  this  piling  is  made  to  act  as  the  armor-coat  for 
receiving  the  waterproofing.  (Fig.  19.)  These  conditions,  however, 
only  occur  on  large  and  difficult  work  where  they  must  be  given 
special  consideration. 

If  the  masonry  armor-coat  against  the  rock  surface  or  sheet 
piling  is  too  wet  to  receive  the  waterproofing,  or  when  the  sheet- 
piling  armor  is  in  a  similar  condition,  then  a  so-called  dry  ply  of  either 
felt  or  fabric,  or  a  combination  of  the  two,  is  first  applied.  Where 
water  is  actually  running  over  the  face  of  the  wall  or  sheet  piling, 
it  should  be  diverted  temporarily.  This  may  be  done  either  by 
inserting  sufficient  bleeders  at  the  best  elevation,  or  by  attaching 
a  strip  of  tin  in  the  shape  of  a  trough  above  the  space  to  be  water- 
proofed. Plaster  of  Paris  or  cement  may  be  used  for  attaching  this 
strip.  If,  by  these  methods,  the  surface  cannot  be  made  thoroughly 
dry,  a  dry-ply  of  felt  and  fabric  combined  is  to  be  hung  up  against 
the  surface.  The  brick-in-mastic  is  then  laid  against  it  in  such  a 
manner  as  to  permit  the  water  to  flow  down  and  progressively  forward 
and  out  from  behind  this  dry  ply.  Wherever  there  is  no  direct  water 
to  contend  against,  as  above  noted,  the  dry  ply  may  consist  of  strips 
of  felt  or  fabric,  mopped  in  the  usual  way.  In  building  the  armor- 


SYSTEMS  OF  WATERPROOFING  59 

coat  of  concrete,  the  form  for  it  should  be  made  rigid  so  as  to  avoid 
bulging.  Neglect  of  this  precaution  causes  a  reduction  in  the  cross- 
section  of  the  brick-in-mastic  wall,  a  condition  to  be  avoided,  as 
eventually  it  may  be  the  cause  of  leaks,  due  to  the  careless  practice 


FIG.  19.— Showing  Partly  built  Main  Wall,  1,  and  Forms  for  Brick  and  Mastic,  2. 
Note  Top  Row  of  Bricks  Covered  with  Mastic,  and  Sheet  Piling  left  in 
Place  Acting  as  Armor  for  Waterproofing. 

of  filling  the  narrow  parts  of  the  forms  with  small  pieces  of  brick,  or 
squeezing  in  whole  bricks  and  thus  thinning  the  joints. 

Precautions  for  Setting-up,  Filling  and  Stripping  Forms  for 
Brick-in-Mastic  Walls.  In  building  brick-in-mastic  walls,  forms 
are  necessary  mainly  to  allow  the  mastic  to  set,  and  in  warm  weather, 
even  after.  Fig.  19  shows  a  form  for  a  two-course  mastic  wall  in 


60 


WATERPROOFING  ENGINEERING 


—  2  Courses 
Brick-in-IVIastic 


FIG.  20.— Building  of  Two-course  Brick-in-mastic  Wall,  Showing  Form,   Form 
Bracing,  and  Sand  Wall. 


SYSTEMS  OF   WATERPROOFING  61 

course  of  construction  against  a  sand  wall  preparatory  to  the  placing 
of  the  finished  wall  within.  Therefore,  after  the  surface  of  the 
armor-coat  has  been  properly  prepared,  the  forms  should  be  placed 
the  required  distance  from  it.  This  distance  is  governed  by  the 
manner  of  laying  up  the  bricks;  i.e.,  if  the  longest  edges  of  the  bricks 
are  perpendicular  to  the  wall  (all  bricks  being  laid  as  headers)  8J 
inches  form  space  is  required;  if  they  are  laid  parallel  to  the  wall 
in  two  courses,  8  inches  are  required,  and  in  single  courses,  4  inches. 
Of  course  this  assumes  the  use  of  common  red  brick,  as  no  better 
or  special  kind  is  necessary.  The  height  of  form  sections  are  not  to 
exceed  3  feet,  so  as  to  enable  the  waterproofer  to  easily  reach  the 
bottom  in  laying  the  bricks.  In  bulkheading  the  forms,  tight 
joints  are  necessary. 

To  insure  the  easy  and  successful  stripping  of  forms,  the  inner 
surfaces  of  the  forms  are  to  receive  a  wash  coat  of  neat  cement,  or 
have  a  strip  of  felt  attached.  Washes  of  lime  or  clay  may  also  be 
used  to  good  advantage,  but  in  no  case  should  lumpy  clay  be 
applied.  Any  of  these  coatings  are  best  applied  before  the  forms 
are  set  up. 

When  the  forms  are  erected,  a  pail  of  mastic  is  poured  and  spread 
uniformly  therein.  The  bricks  are  immediately  embedded  in  the 
mastic,  usually  on  their  largest  bed  and  with  their  longest  edge 
parallel  to  the  wall.  In  laying  the  brick  no  mastic  should  be  allowed 
to  collect  or  extend  beyond  any  course  of  bricks.  In  laying  the 
successive  courses  of  brick,  they  may  be  made  to  break  joints  in  the 
same  manner  as  in  a  brick  and  mortar  wall,  but  this  is  not  essential. 
Where  the  space  between  the  wall  and  the  form  is  not  wide  enough 
to  allow  one  or  two  bricks  as  the  case  may  be  to  be  laid  on  their 
largest  bed  and  with  proper  joints  (in  the  manner  described  above) 
due  to  bulging  of  the  sand  wall  or  armor-coat,  the  bricks  should  be 
laid  so  as  to  leave  more  mastic  in  the  joints  and  faces.  Sometimes 
a  ply  of  fabric  is  added  for  each  inch  of  reduction  of  form  width 
due  to  this  bulging,  but  this  is  inadequate  and  should  be  guarded 
against. 

Settlement  and  Bracing  of  Brick-in-Mastic  Walls.  Where  the 
mastic  forms  must  be  removed  prior  to  the  building  of  the  main 
wall,  the  mastic  wall  should  be  well  braced  to  prevent  buckling  and 
undue  settling.  In  warm  weather  the  removal  of  mastic  forms  should 
be  done  only  shortly  before  building  the  main  wall.  Where  failure 
to  observe  this  rule  has  caused  any  decided  deformation  in  the  mastic 
wall,  this  portion  should  be  cut  out  and  properly  replaced  with  new 
materials.  But  quite  often  it  will  be  possible  to  push  the  bulge  back 


62  WATERPROOFING  ENGINEERING 

into  place  by  applying  a  constant  force,  pressing  on  as  large  an  area 
of  the  bulge  as  possible. 

All  asphalt  mastic  on  cooling  will  reduce  in  volume  and  settle, 
(about  |  inch  in  a  height  of  10  feet  per  30  deg.  Fahr.  (16.5  deg.  Cent.) 
change  in  temperature  for  a  2  :  1  :  1  mastic)  therefore  no  concrete 
should  be  placed  on  top  of  a  mastic  wall  until  complete  cooling  and 
settlement  has  taken  place  in  it.  Neither  should  a  mastic  wall  be 
counted  on  to  carry  any  weight  at  any  time  because  it  cannot  per- 
form this  function  by  the  very  nature  of  its  make-up.  On  extended 
flat  surfaces,  however,  it  can  be  made  to  safely  carry  about  300  pounds 
per  square  inch  at  about  60  deg.  Fahr.  (15.5  deg.  Cent.)  if  movement 
in  the  layers  is  impossible. 

Where  a  mastic  wall  is  to  join  the  brick-in-mastic  on  the  roof  of  a 
structure,  it  should  be  brought  up  to  the  level  of  the  roof-masonry, 
and  allowed  to  settle  and  cool,  then  the  mastic  on  the  roof  should  be 
laid  and  joined  to  the  wall  mastic.  The  protective  concrete  or  other 
masonry  is  then  laid  so  that  its  joints  are  not  directly  over  the  joints 
in  the  mastic  waterproofing. 

Materials  for  Making  Mastic :  their  Properties  and  Proportions. 
Asphalt  or  coal-tar  pitch  may  be  used  for  making  mastic.  Both  must 
be  carefully  selected  and  tested  to  insure  their  adaptability.  The 
usual  practice  is  to  use  a  minimum  of  33  per  cent  of  bitumen,  but  this 
may  be  decreased  to  25  per  cent  where  a  stiff  mastic  is  required,  or 
increased  to  50  per  cent  where  a  less  viscous  mastic  is  desired.  The 
mineral  aggregate,  the  presence  of  which  tends  to  increase  the  tensile 
strength  of  the  binder,  is  usually  sand,  cement  or  limestone  dust, 
and  sometimes  asbestos  fiber  is  added  as  a  filler.  The  proportions 
are  often  arbitrarily  and  carelessly  specified.  The  aim  in  this  regard 
should  be  to  proportion  the  mineral  filler  to  produce  maximum  den- 
sity which  insures  maximum  strength. 

The  sand  for  making  mastic  should  all  pass  through  a  10-mesh 
sieve.  It  should  never  be  used  when  wet  or  moist,  and  in  general, 
should  be  heated  before  using.  (Figs.  77  and  78  show  the  customary 
ways  of  doing  this.)  This  will  lessen  the  formation  of  bubbles  and 
pin  holes  in  the  mastic  caused  by  the  escape  of  the  occluded  moisture. 
The  sand  should  also  be  clean,  free  from  dirt,  silt,  or  vegetable 
matter. 

Any  cement  in  good  condition  is  suitable  for  making  water- 
proofing mastic.  Fineness  of  the  material  is  the  important  factor, 
because  the  finer  the  grain,  the  more  intimate  is  its  incorporation 
with  the  bitumen.  The  limestone  dust  need  not  be  as  fine  as  the 
cement,  but  it  should  pass  at  least  80  per  cent  through  a  100-mesh 


SYSTEMS  OF  WATERPROOFING  63 

sieve,  and  10  per  cent  through  a  200-mesh  sieve.  Slate  dust  is 
sometimes  substituted,  but  it  usually  lacks  the  fineness  of  either 
cement  or  limestone  dust. 

Bricks  used  for  brick-in-mastic  waterproofing  should  be  of  good 
quality  common  brick,  burned  hard  entirely  through,  regular  and 
uniform  in  shape  and  size  and  of  compact  texture.  They  should 
also  be  heated  to  complete  dryness  before  using,  and  so  heated  as  to 
remain  practically  clean,  i.e.,  free  of  excessive  soot.  The  various 
methods  for  doing  this  are  discussed  below. 

The  two-thirds  mineral  aggregate  referred  to  above  may  consist 
of  a  mixture  of  sand  and  cement  or  sand  and  limestone  dust  with  a 
reasonable  amount  (not  more  than  1.5  per  cent),  in  either  case,  of 
asbestos  fiber.  The  latter  material,  however,  may  be  dispensed  with, 
as  it  is  only  necessary  in  special  cases,  as,  for  instance,  on  the  top 
or  final  coating  of  the  mastic  layer  when  this  is  located  a  few  feet 
below  ground  surface.  The  sand  and  cement  is  usually  mixed  in 
equal  proportions  by  weight  or  volume,  but  it  would  be  much 
better  to  mix  these  with  due  regard  to  the  percentage  of  voids  in 
the  sand.  In  the  rare  instances  where  mastic  is  to  be  laid  in  a  very 
wet  location,  more  mineral  matter  should  be  used,  as  this  will 
increase  the  weight  of  the  mastic  and  decrease  the  tendency  to  create 
bubbles  in  the  asphalt  due  to  the  steaming  and  upward  pressure  of 
the  water,  also  when  it  is  to  be  used  on  an  incline,  as  more  sand 
stiffens  the  mastic.  In  the  mastic  that  is  used  as  a  top  coating  for 
the  upper  course  of  bricks,  less  sand  should  be  used.  This  will 
leave  the  mastic  more  ductile  and  plastic,  permitting  it,  if  cracked, 
to  heal  more  readily  when  the  temperature  is  suitable  An  addition 
of  asbestos  fiber  may  be  made  instead  of  reducing  the  sand,  as  this 
also  gives  a  more  flexible  coating. 

Hand-  versus  Machine-made  Mastic.  When  making  water- 
proofing mastic  by  hand,  it  is  important  to  see  that  the  sand  and 
limestone  dust  are  thoroughly  dry.  The  sand  and  cement  or  lime- 
stone dust  are  first  mixed  in  proper  proportions  and  then  put  into 
the  mixing  kettle  after  sufficient  asphalt  has  been  melted  therein. 
The  temperature  of  the  asphalt  mastic  should  be  kept  between  350 
and  400  deg.  Fahr.  (177  and  204  deg.  Cent.)  and  coal-tar  pitch  mastic 
between  275  and  325  deg.  Fahr.  (135  and  163  deg.  Cent.).  The 
aggregate  should  not  be  dumped  into  the  melted  asphalt  but  sprinkled 
into  it.  Stirring  the  mastic  must  be  continued  until  a  uniform  mix- 
ture has  been  obtained.  This  requires  at  least  twenty  minutes  of 
continued  stirring  for  a  50-gallon  kettle. 

On  large  work  a  battery  of  mixing  kettles  is  usually  centrally 


64  WATERPROOFING  ENGINEERING 

located,  but  where  the  particular  waterproofing  jobs  are  beyond  a 
500-foot  radius  from  the  mixing  kettles,  the  mastic  must  be  trans- 
ported in  portable  fire  kettles.  The  mastic  in  the  mixing  kettles 
is  to  be  stirred  before  pouring  into  the  portable  kettles,  and  when  it 
arrives  at  the  place  of  waterproofing,  the  mastic  should  again  be 
stirred  before  pouring  into  the  carrying  pails.  No  mastic  from  the 
hot  portable  kettles  must  be  poured  into  the  carrying  pails  unless 
it  is  to  be  used  immediately,  otherwise  settlement  of  the  aggregate 
results  and  the  uniformity  of  the  mixture  is  destroyed. 

The  practice  of  making  mastic  by  hand  in  open  fire-heated  kettles 
is  as  old  as  the  mastic  industry,  which  began  between  1880  and  1885. 
But,  though  paving  mastic  has  for  many  years  been  made  by  machine, 
floor  and  waterproofing  mastic  continue  to  be  made  by  hand.  This 
is  partly  due  to  the  fact  that  (1)  heretofore  such  mastic  was  not  a 
commonly  used  material,  (2)  natural  rock  asphalt  was  mostly  used 
in  the  belief  that  an  artificial  mastic  was  impossible  or  very  inferior, 
(3)  the  secretiveness  with  which  the  mastic  industry  was  developed,* 
and  (4)  the  comparatively  small  quantities  of  floor  mastic  generally 
called  for  on  any  particular  job. 

Making  reasonably  good  mastic  by  hand  is  of  course  possible. 
But  there  are  many  drawbacks  not  usually  considered.  For  instance; 
the  consistency  of  the  mastic  is  usually  determined  by  the  operator 
and  hence  no  two  batches  are  alike;  neither  are  the  proportions  of 
ingredients  constant,  for  they  are  usually  dumped  in  by  "eye"; 
then,  what  is  worst  of  all,  the  man  mixing  the  mastic  naturally 
desires  to  lighten  his  labor  and  occasionally  either  does  not  suffi- 
ciently mix  the  batch,  or  adds  more  bitumen  than  the  amount 
specified.  All  of  these  objections  would  be  absent  in  a  machine- 
made  mastic,  because  the  ingredients  would  necessarily  have  to 
be  weighed  or  measured,  as  is  done  in  mixing  concrete  by  machine. 
The  quality  would  also  be  easily  regulated  and  the  engineer  could 
better  inspect  the  work  to  see  that  his  specifications  were  lived-up  to, 
especially  in  the  matter  of  cooking  the  mastic.  On  large  work  this 
is  very  important. 

A  type  of  mastic-mixing  machine  which  makes  this  possible, 
and  indeed,  makes  a  superior  mastic,  is  shown  in  Fig.  67.  The 
author,  who  has  experimented  with  and  observed  the  product  of  a 
machine  of  this  type  for  a  long  time,  can  state  confidently  that  it 
would  be  to  the  interest  of  the  mastic  industry  to  abolish  the  hand- 
mixed  product  and  resort  to  a  machine-mixed  mastic,  especially 

:2lln  the  early  days  of  the  mastic  industry  it  was  not  beneath  some  of  those 
engaged  in  it  to  employ  the  tricks  of  witchcraft  to  fool  the  inquisitive. 


SYSTEMS  OF  WATERPROOFING  65 

because  of  its  economy.  This  economy  results  from  the  fact  that 
the  asphalt  does  not  have  to  be  first  melted  and  heated  as  with  the 
use  of  open  kettles,  and  also  because  none  of  the  mineral  aggregates 
needs  preheating.  This  is  all  accomplished  in  the  drum  of  the 
machine,  which,  besides,  can  mix  a  much  larger  batch  in  considerably 
less  time  than  men  can  mix  it  in  open  kettles.  Machine-mixed 
mastic  is,  however,  admittedly  impracticable  on  small  jobs,  and  has 
not  yet  been  used  for  making  waterproofing  mastic  such  as  described 
above,  that  is,  its  use  heretofore  has  been  limited  to  floor  and  paving 
mastic. 

Brick-heating  Methods.  In  the  use  of  bricks  for  brick-in-mastic, 
the  question  often  arises  as  to  (a)  when  the  bricks  should  be  heated, 
(6)  to  what  extent  they  should  be  heated,  and  (c)  by  what  method 
they  should  be  heated.  In  answering  these  questions  experience 
is  the  best  guide.  Bricks  used  as  above  noted  should  be  heated  (a) 
when  the  temperature  is  below  40  deg.  Fahr.  (4.5  deg  Cent.),  (6) 
when  they  are  moist  or  damp  (because  either  condition  prevents 
good  bonding  between  the  bricks  and  the  mastic) ,  (c)  they  should  be 
heated  to  a  degree  not  exceeding  that  which  permits  their  being 
handled  with  the  bare  hands  (because  otherwise  the  mastic  film 
surrounding  the  bricks  will  be  melted  off),  and  (d)  the  method  of 
heating  should  be  such  as  will  not  cover  the  bricks  with  an  over 
amount  of  soot,  because  this  tends  to  prevent  proper  bonding,  and 
bonding  is  very  essential  to  the  continuity  of  the  layer  or  envelope 
of  brick-in-mastic. 

A  method  of  heating  bricks  to  be  strictly  avoided  is  the  following: 
A  small  make-shift  furnace,  constructed  by  enclosing  three  sides  of  a 
convenient  area  with  walls  of  either  brick  or  stone,  laid  dry.  These 
walls  are  of  any  convenient  length  and  about  a  foot  high ;  the  fourth 
side  remains  open  and  through  it  the  fire  is  fed.  On  top  of  the  walls 
is  placed  a  wire  screen  strong  enough  to  support  about  200  or  300 
bricks  piled  promiscuously.  A  wood  fire  is  kindled  underneath 
and  the  heat  and  smoke  pass  up  between  the  bricks.  This  method 
not  only  fails  to  heat  the  bricks  alike  but  also  covers  them  with  more 
or  less  soot,  and  is  slow  and  wasteful. 

A  better  method  is  the  following:  A  hollow  cylinder  about 
4  or  5  feet  in  diameter  is  made  by  piling  bricks  one  upon  the  other 
with  loose  joints,  but  interlocked  so  as  to  make  the  entire  cylinder 
self-supporting.  The  bricks  are  laid  on  their  largest  bed  and  built 
up  to  a  convenient  height,  say  3  or  4  feet.  Next,  a  wood  fire 
is  made  within  the  cylinder,  or,  better  still,  a  coke  fire  is  main- 
tained in  a  salamander  placed  within  the  cylinder.  If  a  wood 


66  WATERPROOFING  ENGINEERING 

fire  is  used  the  flames  should  be  kept  low.  This  scheme  permits 
the  escape  of  smoke  without  covering  the  bricks  with  soot.  The 
radiating  heat  dries  the  bricks  to  any  desired  degree  depending 
on  how  long  they  remain  near  the  fire.  If  a  second  row  of  bricks  is 
built  around  the  first  one  it  will  receive  its  incipient  heat  and  as  the 
inner  cylinder  of  bricks  is  used  up  the  outer  one  will  gradually  receive 
its  share  of  heat.  This  method,  however,  is  also  slow.  A  mechani- 
cal brick  heater  is  described  in  Chapter  VI,  and  is  the  most  efficient 
means  for  heating  and  drying  bricks  known  to  the  author. 

Weather  Conditions  Governing  Waterproofing  Operations.  To 
obtain  the  best  results,  no  waterproofing  should  be  done  wherein 
ordinary  bitumen  is  used  as  the  cementing  or  binding  material, 
especially  in  the  form  of  a  membrane,  sheet  mastic,  or  brick-in- 
mastic  layers,  when  the  air  temperature  is  below  40  deg.  Fahr. 
(4.5  deg.  Cent.),  nor  during  snow,  rain,  or  drizzle.  Coal-tar  pitch 
chills  rapidly  in  cold  weather  and  will  not  stick  well  to  cold  masonry; 
and  asphalt  is  even  less  adhesive  to  cold  masonry.  Neither  pitch 
nor  asphalt  will  adhere  to  a  wet  surface,  therefore  these  conditions 
must  be  avoided.  However,  if  the  work  be  amply  protected  from 
cold  and  wet  weather,  waterproofing  may  proceed  with  due  precau- 
tions for  eliminating  the  hazards  of  these  conditions.  On  the  other 
hand,  in  warm  weather,  care  must  be  taken  to  protect  the  finished 
waterproofing  promptly,  especially  if  it  is  exposed  to  the  sun,  other- 
wise expensive  repairs  may  become  necessary,  before  or  soon  after 
completion  of  the  work. 

INTEGRAL  SYSTEM  OF  WATERPROOFING 

Definition,  Purpose  and  Development.  The  integral  system  of 
waterproofing  is  the  process  of  making  impermeable  mortar  or  con- 
crete by  incorporating  in  the  mass,  certain  ingredients  which  act 
either  as  void  fillers,  as  lubricants  for  the  aggregate,  or  chemically 
upon  the  cement,  thus  densifying  the  mass.  These  ingredients  con- 
sist of  (1)  finely  ground  powders,  such  as  clays,  silicates,  feldspars 
and  hydrated  lime,  which  are  usually  mixed  with  the  dry  cement 
at  the  mill  or  on  the  work;  (2)  liquids  and  pastes  such  as  stearate  of 
lime  (water-insoluble  soap),  sodium  or  potassium  oleate  (water- 
soluble  soap),  aluminum  stearate,  calcium  chloride  and  oil  com- 
pounds, which  are  usually  mixed  with  the  gaging  water,  though 
they  are  sometimes  added  to  the  mixed  mass  to  form  an  integral 
part  of  the  resulting  mortar  or  concrete. 

The  fillers  may  be  inert  or  active.     If  inert,  as  the  above  powders 


SYSTEMS  OF  WATERPROOFING  67 

are,  they  merely  fill  up  the  pores  or  voids  inherent  in  the  concrete, 
but  if  active,  as  the  above  soap  compounds  are,  they  may  either 
unite  with  the  cement  or  crystallize  in  themselves.  The  resulting 
compounds  tend  either  to  fill  the  voids  and  barricade  the  pores  or  to 
become  water  repellent.  Most  of  the  liquids  and  some  of  the  pow- 
ders are  inactive  lubricants  of  a  fatty  nature,  and  these  assist  the 
aggregates  to  slide  more  compactly  into  place. 

The  purpose  of  the  integral  system  of  waterproofing  is  to  make 
concrete  and  mortar  impermeable  by  the  application  of  the  water- 
proofing materials  during  the  process  of  mixing,  thus  reducing  the 
cost  of  the  construction  by  eliminating  the  necessity  for  any  addi- 
tional treatment.  This  system  of  waterproofing,  however,  does  not 
remove  the  need  for  thorough  mixing  and  careful  placing  of  the 
concrete. 

The  integral  system  of  waterproofing  is  best  adapted  for  treat- 
ment of  structures  in  the  course  of  construction,  principally  of  the 
type  not  subject  to  vibration  or  shock.  For  water  tanks,  dams, 
foundations,  and  other  stationary  or  rigid  concrete  structures,  where 
absorption  or  percolation  through  the  concrete  may  work  serious 
havoc,  it  is  particularly  well  adapted.  However,  the  possibilities  of 
making  mass  concrete  impermeable  by  the  simple  expedient  of  care- 
fully grading  and  correctly  proportioning  the  aggregate  and  pro- 
longing the  time  of  mixing  should  not  be  forgotten.  For  railroad 
subways  and  bridge  floors,  this  system  should  not  be  specified,  no 
matter  how  promising  may  be  the  materials  offered;  for,  even  if  the 
waterproofing  materials  added  do  not  weaken  the  concrete  (as 
sometimes  happens  when  inferior  compounds  are  used),  they  cannot 
prevent  its  cracking  under  vibration  of  traffic  and  the  consequent 
percolation  of  water  through  such  cracks. 

The  incorporation  of  foreign  ingredients  in  mass  concrete  to 
increase  its  density,  or,  what  amounts  to  the  same  thing,  decrease 
its  permeability,  is  not  so  very  old.  Originally  quick  lime  was  used, 
then  certain  patented  compounds  began  to  appear  on  the  market, 
such  as  stearates  and  resinates  (water-insoluble  substances),  and 
finally  hydrated  lime  began  to  be  used  for  this  purpose.  In  recent 
times  numerous  secret  and  patented  compounds  have  been  exten- 
sively used,  but  owing  to  a  general  dissatisfaction  with  the  results 
obtained,  they  have  received  a  considerable  setback.  And  with 
them  some  very  good  materials  were  thrown  into  disrepute.  The 
practice  of  adding  an  arbitrary  but  small  percentage  of  cement 
over  and  above  the  calculated  amount  is  quite  prevalent,  and  often 
accomplishes  the  results  claimed  for  many  of  these  special  compounds, 


68  WATERPROOFING  ENGINEERING 

Limitations  of  the  Integral  System  of  Waterproofing.     The  use 

of  integral  waterproofing  compounds  should  be  limited  to  conditions 
where  certainty  exists  regarding  character  of  stresses  in  the  structure, 
and  then  only  after  the  materials  have  been  analyzed,  tested  and 
proven  efficient.  The  following  pertinent  remarks  by  the  U.  S. 
Bureau  of  Standards*  corrobate  the  foregoing:  "  The  addition  of 
so-called  integral  waterproofing  compounds  will  not  compensate 
for  lean  mixtures  nor  for  poor  materials,  nor  for  poor  workmanship 
in  the  fabrication  of  the  concrete.  Since  in  practice  the  inert 
integral  compounds  (acting  simply  as  a  void-filling  material)  are 
added  in  such  small  quantities  they  have  very  little  or  no  effect 
on  the  impermeability  of  the  concrete.  If  the  same  care  be  taken 
in  making  the  concrete  impermeable  without  the  addition  of  water- 
proofing material,  as  is  ordinarily  taken  when  waterproofing  materials 
are  added,  an  impermeable  concrete  can  be  attained." 

The  incorporation  of  any  kind  of  integral  waterproofing  material 
into  a  mass  of  concrete  will  not  materially  prevent  the  formation  of 
hair  cracks  or  temperature  cracks  or  cracking  due  to  uneven  settle- 
ment. Results  with  different  materials  will  vary,  but  very  few 
have  proven  entirely  satisfactory.  Neither  can  this  system  prevent 
seepage  through  day's  work  planes,  and  expansion  joints,  or  joints 
between  steel  and  concrete.  Furthermore,  this  system  of  water- 
proofing, or  rather  the  materials  used  in  connection  therewith,  may 
reduce  the  strength  of  concrete  and  sometimes  may  even  induce 
disintegration  in  the  concrete.  The  integral  waterproofing  materials 
that  will  not  do  these  things  are,  in  fact,  few,  and  their  successful 
use  requires  so  much  care  and  labor  that  better  results  may  often 
be  obtained  by  the  self-densified  system  of  waterproofing,  f  In  the 
light  of  present-day  knowledge  and  experience  with  integral  water- 
proofing compounds,  their  use  and  need  are  debatable  on  the  basis 
of  real  efficiency.  There  are  many  cases,  nevertheless,  where  any 
other  system  of  waterproofing  as  well  as  the  integral  system  might 
be  used  with  equally  good  results,  the  selection  under  such  cir- 
cumstances, being,  of  course,  a  comparison  of  costs.  The  integral 
system  has,  however  an  advantage  always  worthy  of  consideration, 

*  Technologic  Paper  No.  3,  p.  83. 

fThe  author  is  able  to  say  that  several  manufacturers  of  integral  water- 
proofing materials  have  admitted  this  to  him,  but  they  asserted  that  these 
materials  are  worth  their  cost  merely  by  acting  as  a  factor  of  safety.  It  seems 
more  probable,  however,  that  these  materials  act  more  psychologically  than  as  a 
safety  factor.  That  is  to  say,  workmen  will  probably  feel  more  inclined  to 
prolong  the  mixing  and  tamp  more  vigorously  when  told  or  shown  that  some- 
thing has  been  added,  but  which  will  really  be  effective  only  by  such  activity. 


SYSTEMS  OF  WATERPROOFING  60 

namely,  it  requires  no  additional  excavation  or  protective  masonry, 
and  the  waterproofing  operation  proceeds  with  the  construction, 
which  is  often  a  great  advantage.  In  justice  to  some  materials  of  this 
type  that  have  apparently  given  satisfaction,  it  must  be  admitted 
that  there  is  really  great  need  for  more  extensive,  and  exhaustive 
practical  tests,  that  is  service  tests,  on  this  entire  class  of  materials. 

INTEGRAL  WATERPROOFING  MATERIALS  AND  THEIR  APPLICATION 

The  types  of  materials  above  mentioned  namely,  po*wders, 
pastes  and  liquids,  will  now  be  considered  in  a  more  detailed  manner. 
The  many  integral  compounds  appearing  on  the  market  are  mostly 
of  a  water-repellent  nature,  but  their  compositions  are  seldom 
divulged,  except  those  which  are  patented.  The  powders  are  usually 
of  a  white,  floury  consistency,  and  water-repellent.  This  property 
is  imparted  to  them  by  the  addition  of  some  metallic  stearate  such  as 
limesoap,  which  is  of  a  fatty  nature.  The  fineness  of  the  powders 
gives  them  their  void-filling  properties,  while  those  of  a  fatty  nature 
act  also  as  a  lubricant  for  bringing  into  closer  proximity  the  con- 
stituent materials  of  the  concrete.  The  addition  to  the  concrete 
mass  of  various  amounts  of  hydrated  lime  also  creates  a  dense  mixture 
by  the  same  procress. 

Use  of  Hydrated  Lime.  In  regard  to  the  addition  of  hydrated 
lime,  experience  has  demonstrated  that  it  serves  to  increase  the 
plasticity  and  also  to  lubricate,  as  it  were,  the  aggregate  of  the  con- 
crete, resulting  in  a  denser  and  more  uniform  mass.  But  the  United 
States  Bureau  of  Standards*  states  that  the  value  of  hydrated  lime 
as  a  waterproofing  medium  is  probably  due  to  its  void-filling  prop- 
erties, and  that  the  same  results  could  be  expected  from  any  other 
finely  ground  inert  material,  such  as  sand  or  clay.  While  this  is 
true,  it  is  none  the  less  an  indisputable  fact  that  hydrated  lime  acts 
in  a  greater  measure  as  a  lubricant,  which  the  others  would  only  do 
in  a  very  limited  way.  Many  proprietary  compounds  are  composed 
mainly  of  finely  ground  sand  and  clay. 

By  adding  from  10  to  15  per  cent  of  hydrated  lime,  the  tendency 
of  concrete  to  check  and  hair  crack  is  materially  reduced,  as  the 
lime  absorbs  and  retains  a  large  percentage  of  water  and  therefore 
holds  the  moisture  in  freshly  poured  concrete  until  the  slower  acting 
cement  can  utilize  it. 

Mr.  Sanford  E.  Thompson,!  in  a  series  of  experiments  on  the 

*  Technologic  Paper  No.  3. 

t  American  Society  for  Testing  Materials,  June,  1908. 


70 


WATERPROOFING   ENGINEERING 


effects  of  hydrated  lime  in  concrete,  arrived  at  the  figures  in  Table 
IV  in  regard  to  the  effective  proportions  of  hydrated  lime  for  pro- 
ducing water-tight  concrete. 

TABLE  IV.— PROPORTIONS  OF  HYDRATED  LIME  FOR  IMPERVIOUS 

CONCRETE 


Portland 
Cement 
(Parts). 

Sand 
(Parts). 

Stone 
(Parts). 

Hydrated 
Lime 
(Per  Cent). 

1 

2 

4 

8 

1 

2.5 

4.5 

12 

1 

3 

5 

16 

The  percentage  of  lime  is  in  terms  of  weight  of  cement.  The 
sand  and  stone  are  representative  of  average  materials  throughout 
the  country.  The  coarser  the  sand,  however,  the  more  lime  should 
be  used. 

Lime  paste  occupies  more  than  two  times  the  bulk  of  paste  made 
from  an  equal  weight  of  Portland  cement.  Hence,  by  replacing 
the  cement  in  mortar  by  about  15  per  cent  of  hydrated  lime, 
its  density,  and  in  consequence  its  strength  and  permeability  are 
increased. 

But  even  with  the  addition  of  hydrated  lime,  the  concrete 
materials  must  be  graded,  and 'the  proper  proportions  of  cement  and 
hydrated  lime  used.  If  the  concrete  is  poorly  mixed  or  made  with 
insufficient  water,  or  improperly  placed,  or  if  joints  are  left  unpro- 
tected, the  structure  will  inevitably  leak.  The  mixing  must  be 
thorough,  sufficient  water  must  be  employed  to  give  a  "  mushy  " 
mixture  so  that  it  will  settle  into  place  with  the  least  amount  of 
ramming.  Fully  as  important  as  the  care  in  mixing  is  the  bonding 
of  one  day's  layer  of  concrete  with  the  next;  even  small  inter- 
ruptions of  an  hour  on  a  hot  day  will  materially  injure  the  bond  of 
the  concrete. 

Use  of  Inert  Fillers.  Inert  fillers  vary  greatly  in  durability  and 
resistive  properties,  and  should  therefore  be  selected  with  con- 
siderable care.  A  governing  property  of  all  inert  fillers  is  that  they 
should  not  only  be  inert  in  the  presence  of  the  cement  but  also  to 
atmospheric  moisture  and  gases  and  percolating  waters. 

Many  fillers  now  used  consist  of  clay,  sand,  lime  and  ordinary 
natural  or  Portland  cement,  this  latter  in  a  form  exceedingly  finer 
than  ordinarily  used,  or  in  the  form  of  "  excess  quantity  "  to  make 
a  rich  mixture  of  the  mass  of  mortar  or  concrete. 


SYSTEMS  OF  WATERPROOFING 


71 


The  chemical  composition  of  some  inert  powder  fillers  are  given 
in  Table  V  together  with  a  comparative  analysis  of  average  Portland 
and  natural  cements.  The  first  two  are  taken  from  a  Technologic 
Paper  of  the  United  States  Bureau  of  Standards*  together  with  part 
of  the  following  remarks: 

"  Those  materials  which  act  as  void  fillers  or  increase  the  density 
of  the  concrete  and  are  without  any  action  on  the  cement  and  do  not 
themselves  change,  are  known  as  inert  fillers.  Included  in  this  class 

TABLE  V.— ANALYSIS  OF  INERT  FILLERS 

(CLAYS,  SAND,  FELDSPAR  AND  HYDRATED  LIME) 


N.  Y. 
Clay. 

Mo. 
Clay. 

Feldspar. 

Sand. 

Hydrated 
Lime. 

Silica                   

58  30 

72.91 

64  02 

89  50 

1  34 

Alumina 

16  85 

15  01 

19  38 

2  36 

45 

Ferric  oxide  
Manganese  oxide 

6.41 
06 

2.79 
03 

.70 
trace 

2.58 
12 

.13 

Lime  
Magnesia              

4.22 
2.92 

.59 

.85 

.87 
33 

1.37 
57 

46.90 
32  19 

Sulphuric  anhydride  (SO:.)  . 
Sodium  oxide  
Potassium  oxide     

.12 

.77 
2.71 

.12 
.80 
2  12 

.10 
2.52 
11  76 

.21 

.26 
70 

4.02* 
15  05f 

Water  (105°)  

.60 

1.12 

.06 

.20 

Ignition  loss  

7.00 

3.81 

54 

2.35 

99.96 

100.15 

100.28 

100.22 

100.08 

*  Carbon  dioxide. 


t  Total  water. 


are  hydrated  dolomitic  lime,  clays,  finely  ground  sand,  and  finely 
ground  feldspar.  Some  of  these  may  be  partly  changed  in  time 
when  in  the  concrete.  The  hydrated  lime  may  be  partly  carbonated, 
especially  on  the  surface;  the  feldspar  may  decompose  by  the 
leaching  out  of  the  alkalies;  the  sand  will  change  but  very  little, 
if  composed  of  a  high-grade  quartz  sand ;  the  clays  will  be  very  inert, 
although  some  theories  have  been  brought  forward  which  assume  a 
very  important  role  for  clay  when  mixed  with  concrete ;  this  is  to  the 
effect  that  the  colloids  of  the  clay  protect  the  calcium  compounds 
from  quick  hydration,  and  consequently  prevent  increase  in  volume 
due  to  chemical  action."  However,  reliable  data  show  that  the 
addition  of  clay  to  concrete  or  mortar  decreases  their  permeability 
considerably  and  even  increases  their  strength  to  a  slight  degree. 
But  the  use  of  clay  as  balanced  against  the  addition  of  extra  cement 
*  Technologic  Paper  No.  3,  p.  44. 


72  WATERPROOFING  ENGINEERING 

to  accomplish  the  same  results  should  be  carefully  considered, 
especially  in  the  light  of  a  comparison  of  costs.  For,  reasonably  good 
clay  must  be  used,  and  unless  cheaply  obtained  the  balance  will 
invariably  be  in  favor  of  the  cement.  Plain  blue  brick  clay  and  pure 
white  Georgia  clay  may  be  used  with  good  results  as  inert  void 
fillers. 

Use  of  Active  Fillers.  Active  fillers  consist  of  compounds  which 
react  with  certain  constituents  of  the  cement,  thus  forming  new 
compounds  which  are  themselves  inert  and  either  barricade  or  fill 
up  the  voids.  In  most  of  these  compounds  on  the  market  the  active 
fillers  form,  but  a  small  percentage  of  the  compound  proper  as 
illustrated  by  the  analysis  in  the  first  column  of  Table  VI.  "  This 
compound  was  a  white  powder  with  a  strong  aromatic  odor  of 
Kauri  resin.  It  was  in  fact  partly  a  resinate  of  potash,  which 
would  be  decomposed  by  the  lime  present  to  the  corresponding  lime 
rcsinate,  which  is  comparatively  insoluble.  The  great  part  of  the 
compound  is  entirely  inert,  being  china  clay  and  hydrated  lime. 

"As,  however,  in  themselves  these  materials  are  not  waterproofing, 
but  become  so  only  as  a  result  of  a  series  of  reactions,  it  would  be 
better  to  use  the  result  of  these  reactions  directly  and  not  depend 
upon  something  that  may  not  always  take  place  either  wholly  or 
in  part." 

Use  of  Proprietary  Cements.  Some  proprietary  cements  are 
compounds  made  of  Portland  cement  that  has  been  altered  by  the 
addition  of  either  stearates  of  lime,  or  soda  and  potash,  sand,  and 
other  materials  and  specially  treated  until  the  mass  becomes  a  water- 
repellent  cement.  Again,  some  waterproof  cements  are  made  by 
mixing  about  5  per  cent  (by  weight)  of  a  lime-oil  compound  in 
clinker  form,  with  Portland  cement  clinker  and  grinding  them 
together.  The  powder  formed  is  then  used  as  ordinary  cement, 
and  results  in  a  more  or  less  dense  concrete,  not,  however,  in- 
dependent of  the  necessary  care  in  mixing  and  placing.  Another 
form  of  compound  of  this  nature  consists  of  fish-oil  boiled  in  hydro- 
chloric acid,  then  mixed  with  burnt  lime  while  slaking  with  water, 
the  resulting  product  being  a  paste  which  dries  and  hardens  as 
clinker.  Another  similar  compound  is  made  by  combining  a  pow- 
dered resinate  compound  consisting  of  copal  gum,  hydrated  lime  and 
fine  clay  in  proportion  of  1  :  1  :  1  by  weight  with  Portland  cement, 
the  use  of  which  tends  to  make  waterproof  mortar  or  concrete.  These 
compounds  are  also  used  for  surface  coatings  as  well  as  direct  cements. 
When  used  as  a  direct  cement,  the  lime-oil  cement  compounds  depend 
for  their  impervious  tendencies  upon  the  formation  of  stearates  of 


SYSTEMS  OF  WATERPROOFING 


73 


1. 

6? 

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r 

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SMENT.* 

L 

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<M                    0 

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H 

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llllJilll 

74 


WATERPROOFING  ENGINEERING 


lime  which  are  practically  insoluble  in  water,  and  the  presence  of  a 
large  amount  of  hydrated  lime,  which  also  acts  as  a  lubricant  and 
inert  void  filler.  On  the  other  hand,  the  stearates  of  soda  and  potash 
are  ordinary  soap,  readily  soluble  in  water.  With  these  soaps  a 
reaction  occurs  when  they  are  treated  with  water  in  the  presence  of 
cement;  the  soda  or  potash  is  dissolved  and  the  more  insoluble 
lime  soaps  are  precipitated.  If  this  kind  of  cement  is  used  as  a  sur- 
face coating,  however,  it  is  doubtful  whether  the  above  reactions 
take  place  in  a  sufficient  quantity  of  the  soap  to  effect  proper  water- 
proofing properties  before  it  is  dissolved  and  washed  off  the  surface. 
Experience  indicates  that  in  general,  soap  solutions  do  not  bring 
lasting  results  as  a  waterproofing  agent.  Several  cements  of  this 
nature  have  been  analyzed  by  the  United  States  Bureau  of  Standards 
with  the  results  shown  in  Table  VII.* 


TABLE   VII.— ANALYSES  OF  PROPRIETARY  CEMENTS  USED  FOR 

WARERPROOFING 


Compound  Used  as 
Direct  Cement 

Compound  Used  as 
Coating* 
(Cement  Content) 

Silica                           

23   75% 

22  40% 

Alumina/ 

5  96 

7  98 

Iron  oxide 

1  97 

3  63 

Lime                            

64.44 

59.34 

IVIajrnesia                                 r 

0.91 

1.85 

Sulphuric  anhydride  (SO  ). 

1  21 

1.15 

Sodium  oxide 

0  11 

Potassium  oxide      

0.73 

Ignition  loss                     

1.07 

100.15 

Carbon  dioxide                

C.52 

2.16 

fOrcanic  (fat  acid)                  

0.10 

0.32 

Water                

0.45 

0.93 

99.76 

*This  compound  consists  of  Portland  cement  (27.73%)  and  sand  (72.27%).  The  sand 
(all  passing  one-eighth  sieve),  is  mixed  with  the  cement,  and  is  composed  of  quartzite  and 
dolomite;  there  is  also  a  trace  of  fat  acids  present. 

t  The  organic  is  fat  acids  with  a  melting  point  of  52  deg.  Fahr.  and  present  as  a  lime  soap. 

Use  of  Integral  Liquids.     The  liquids  are  mainly  composed  of 
metallic  salts,  such  as  chloride  of  lime;    they  also  consist  of  oil 
emulsions  and  soap  solutions,  and  solutions  of  paraffin  in  benzine 
*  Technologic  Paper  No.  3,  pp.  41  and  47. 


SYSTEMS  OF  WATERPROOFING  75 

or  benzol.  But  the  paraffin  solutions  are  usually  not  added  to  the 
gaging  water,  these  being  applied  to  a  masonry  surface  with  a  brush 
as  explained  under  the  surface-coating  system.  The  waterproofing 
properties  of  these  liquids  are  derived  from  the  formation  of  gela- 
tinous coatings  around  the  smallest  particles  of  the  constituents 
of  the  masonry.  Of  course,  this  would  tend  to  decrease  the  strength 
of  the  concrete,  and  often  does.  There  is  also  a  coal-tar  product 
used  as  an  integral  waterproofing  from  which  the  volatile  oils  have 
been  almost  entirely  removed,  and  the  remaining  materials  tend  to 
bind  together  the  particles  of  cement  and  fill  the  voids  in  the  concrete. 
Some  other  compounds  are  composed  of  fish  oil  and  water  glass 
(sodium  silicate).  The  fish  oil,  which  is  semi-drying,  is  slowly 
saponified  by  the  lime  of  the  cement,  and  the  water  glass  forms  a 
lime  silicate,  both  actions,  however,  being  incomplete,  due  to  the 
insufficiency  of  lime  present  in  the  cement  for  such  action.  Analyses 
of  a  fish-oil  compound  and  one  of  calcium  chloride  follow.* 

Fish-oil  Compound.  Calcium  Chloride  Compound. 

Soap     1 .05%      Silica trace 

Oil 47 . 29          Alumina  and  iron  oxide 0 . 25% 

Ash  water  glass 11 . 64          Calcium  chloride 27 . 19 

Volatile  (water) 40 . 02  Magnesium 0 . 04 

Water  (and  iron  resinate  15%)  72 . 52 

Use  of  Integral  Pastes.  Most  pastes  are  soluble  mixtures  of 
secret  ingredients  which  derive  their  waterproofing  properties  by  the 
precipitation  of  insoluble  materials  in  the  voids  of  the  concrete. 
Some  also  act  so  as  to  consolidate  the  mass  by  increasing  its 
plasticity.  These  contain  either  fine  clay,  lime,  or  colloidal  matter, 
or  all  of  these. 

Sometimes  pastes  are  made  by  mixing  a  powder,  such  as  alum,  to 
the  cement,  and  a  soap  solution  to  the  tempering  water.  In  making 
the  concrete  this  paste  is  added,  and  the  two  constituents  combine 
to  form  a  stearate  of  aluminum  which,  as  noted  before,  is  a  stable, 
water-insoluble,  void-filling  compound. 

In  the  employment  of  integral  pastes  or  any  of  the  above  com- 
pounds it  is  advisable  first  to  investigate  the  efficacy  of  the  materials 
by  inspection  of  results  accomplished  on  previous  work.  By  sub- 
mitting samples  for  analysis  to  qualified  chemists,  or  by  sending 
them  to  the  United  States  Testing  Laboratory  the  following  neces- 
sary information  can  be  obtained  for  a  nominal  cost:  (a)  effect  on 
the  strength  of  the  concrete;  (b)  waterproofing  properties  when 
subjected  to  extreme  ranges  of  temperature;  (c)  effect  of  common 
*  United  States  Bureau  of  Standards,  Technologic  Paper  No.  3,  p.  48 


76  WATERPROOFING  ENGINEERING 

acids  and  alkalies  on  their  waterproofing  properties;  (d)  effect  on 
steel  reinforcement,  i.e.,  if  productive  or  preventive  of  corrosion,  etc. 
In  all  cases  the  manufacturer's  written  instructions  should  be 
followed  with  due  observance,  of  course,  to  any  special  conditions 
arising  on  the  work  necessitating  variation  or  change  of  manipulation. 

SELF-DENSIFIED  CONCRETE 

Definition,  Purpose  and  Development.  The  system  of  water- 
proofing, or,  more  properly  speaking,  the  practice  of  making  imper- 
meable concrete  or  mortar  by  means  of  self-densification,  is,  as  the 
name  implies,  a  process  of  proportioning  the  constituent  materials 
and  mixing  them  so  as  to  create  as  dense  a  finished  mass  as  possible. 
This  is  as  difficult  to  obtain  as  it  is  finally  effective  in  producing 
watertight  concrete.  The  reason  for  this  difficulty  is  that  the 
requisite  density  is  dependent  upon  varying  factors,  the  ones  most 
frequently  militating  against  density  being  the  lack  of  interest  and 
inevitable  fatigue  of  the  labor  employed  together  with  the  uncer- 
tainty of  obtaining  the  specified  quality  and  exact  amount  of  materials 
for  each  batch  without  exceptional  precautionary  measures. 

The  self-densifying  system  of  waterproofing  like  the  integral 
system  is  adapted  to  any  kind  of  mortar  or  concrete  structure  not 
subject  to  severe  vibration,  undue  settlement  or  extreme  variations 
in  temperature,  unless  the  movements  due  to  such  settlement  or 
temperature  changes  are  taken  care  of  by  properly  located  and 
waterproofed  expansion  joints.  Its  main  purpose,  however,  is  to 
eliminate  the  use  of  any  form  of  waterproofing,  because  of  the  extra 
cost  of  materials,  and  the  requisite  time,  labor,  and  attention  neces- 
seary  in  the  application  or  incorporation  of  most  forms  of  water- 
proofing compounds.  If  the  energy  spent  in  preparing  and  applying 
waterproofing  materials  were  expended  on  careful  proportioning, 
mixing,  and  supervision  in  making  the  mass  concrete  or  the  mortar, 
the  engineer  would  obtain  more  nearly  impervious  masonry.  The 
supervision  required  in  either  case,  to  obtain  the  best  results,  is  in 
fact,  about  the  same. 

The  origin  of  self-densified  concrete  is  probably  coincident  with 
the  origin  of  making  concrete.  In  attempting  to  duplicate  natural 
stone  in  strength,  it  was  but  one  step  further  to  attempt  to  make  the 
concrete  as  dense  as  such  stone.  This  probably  led  to  the  develop- 
ment of  a  form  of  cement  so  fine  in  itself  as  to  have  practically  no 
voids  whatsoever.  Such  a  fine-ground  cement  carries  more  sand, 
and  makes  denser  and  more  impervious  concrete  than  the  cement 


SYSTEMS  OF  WATERPROOFING  77 

of  the  old  standard  of  fineness.  This  standard  of  fineness  was  5 
per  cent  passing  a  2500-mesh  sieve,  as  against  78  per  cent  passing  a 
200-mesh  sieve  of  the  present-day  standard.  But  only  in  com- 
paratively recent  times  was  the  further  discovery  made  of  the  value 
of  proportioning  the  constituents  of  concrete  in  such  a  manner 
that  the  voids  of  the  stone,  or  largest  aggregate,  are  completely 
occupied  by  the  sand,  the  voids  of  the  sand  by  the  cement,  and 
the  whole  united  by  the  hydration  of  this  cement  in  the  presence  of 
water.  Though  this  is  theoretically  correct,  in  practice  it  is  found 
necessary  to  use  about  10  per  cent  of  extra  cement  to  obtain  the  best 
results;  first,  because  of  incomplete  hydration  of  the  cement; 
secondly,  because  of  the  practical  impossibility  of  exact  grading  of 
aggregates;  thirdly,  because  of  insufficient  mixing,  tamping  and 
supervision  of  details. 

Methods  of  Making  Dense  Concrete.  Concrete  may  be  mixed 
either  by  hand  or  by  machine,  both  methods,  if  properly  applied, 
giving  about  the  same  grade  of  concrete,  though  the  balance  is 
always  in  favor  of  machine-mixed  concrete.  The  work  done  by 
hand  is  likely  to  be  uneven  in  quality,  and  some  batches  will  be  less 
thoroughlly  mixed  than  others,  while  machine-mixed  concrete  is 
usually  of  a  more  uniform  quality  and  is  generally  less  expensive. 
Hand-mixed  concrete  is  employed  only  when  the  quantity  is  small 
or  when  machinery  is  unobtainable,  but  not  where  uniformly  dense 
and  impervious  concrete  is  an  essential  factor. 

The  fundamental  requirements  for  obtaining  self-densified 
mortar  or  concrete  are:  (1)  destruction  of  the  inherent  porosity 
of  the  mortar  or  concrete;  (2)  scientific  proportioning  of  aggregates; 
(3)  careful  supervision  and  good  workmanship. 

The  inherent  porosity  of  concrete  is  due  partly  to  the  fact  that 
only  about  20  per  cent  of  the  cement*  used  in  making  concrete  is 
hydrated,  or,  in  other  words,  acts  as  a  cementing  material,  the  other 
80  per  cent  remains  lying  in  the  pores  as  so  much  inert  matter,  but 
only  partly  closing  the  pores;  and  partly  to  the  fact  that  since  every 
62J  pounds  of  water  weight  in  concrete  occupies  1  cubic  foot  of  space, 
which  amount  of  water,  if  lost  by  evaporation  or  drainage  during  the 
setting  period,  means  1  cubic  foot  of  voids  remaining  in  the  mass. 
Again,  improperly  graded  aggregate  or  poorly  proportioned  mixtures, 
or  both,  are  very  conducive  to  porosity  in  concrete  and  not  so  easily 
remedied.  Too  much  water  and  too  little  mixing  are  factors  in  the 
workmanship  which  often  results  in  porous  concrete. 

*  See  series  of  articles  on  microscopic  study  of  concrete  by  N,  C,  Johnson, 
in  Engineering  Record,  January,  February,  March,  1915, 


78  WATERPROOFING  ENGINEERING 

The  porosity  due  to  the  first  two  causes,  i.  e.,  insufficient 
hydration  and  excessive  evaporation,  may  be  reduced,  first,  by 
mixing  each  batch  longer  than  is  now  common  in  practice  (with  the 
significant  slogan  in  the  industry  of  "  a  batch  a  minute  "),  and, 
secondly,  by  mixing  with  just  sufficient  water  to  obtain  a  medium 
or  mushy  consistency.  Concrete  of  this  consistency  may  be  defined 
as  a  mixture  of  cement,  sand,  and  stone  or  gravel  of  jelly-like  con- 
sistency, which  is  not  watery,  but  can  be  spaded  and  readily 
worked  into  place  in  the  form.  This  consistency  is  illustrated 
in  Fig.  21.* 

Coarseness  of  sand  and  aggregate,  is  also  effective  in  reducing 
porosity  and  absorption,  although  gravel  seems  to  produce  the 
denser  concrete,  f  In  fact,  gravels  are  preferable  to  crushed-stone 
aggregate,  particularly  for  underwater  work,  because  they  mix 
and  settle  in  place  more  easily.  Either  crushed  stone  or  gravel 
may  be  used,  however,  if  carefully  handled.  But  bank-run  gravel 
should  never  be  used,  as  its  quality  is  not  uniform. 

Scientific  Proportioning.  The  second  essential  requirement  for 
the  production  of  impermeable  mortar  or  concrete  is  scientific 
proportioning.  It  is  of  the  greatest  importance  that  concrete 
should  be  made  as  dense  as  possible  if  it  is  to  be  made  impervious, 
that  is,  that  it  should  have  the  smallest  practicable  percentage  of 
voids.  This  is  best  accomplished,  or,  at  least,  the  various  methods 
tending  toward  this  result  in  practice  are  as  follows :  1 

(1)  Arbitrary  selection;   one  arbitrary  rule  being  to  use  half  as 
much  sand  as  stone,  as  1  :  2  :  4  or  1  :  3  :  6;  another,  to  use  a  volume 
of  stone  equivalent  to  the  cement  plus  twice  the  volume  of  the  sand, 
such  as  1  :  2  :  5  or  1  :  3  :  7. 

(2)  Determination  of  voids  §  in  the  stone  and  sand,  and  pro- 
portioning the  materials  so  that  the  volume  of  sand  is  equivalent  to 
the  volume  of  voids  in  the  stone  and  the  volume  of  cement  slightly  in 
excess  of  the  voids  in  the  sand. 

(3)  Determination  of  the  voids  in  the  stone,  and,  after  selecting 
the  proportions  of  cement  to  sand  by  .test  or  judgment,  proportion- 
ing the  mortar  to  the  stone  so  that  the  volume  of  mortar  will  be 
slightly  in  excess  of  the  voids  in  the  stone. 

*  Technologic  Paper  No.  3,  Bureau  of  Standards,  Washington,  D.  C. 

t  Engineering  News-Record,  Vol.  79,  No.  16,  p.  740.     1917. 

J  "  Proportioning  Concrete,"  by  Sanford  E.  Thompson,  Journal,  Association 
Engineering  Societies,  Vol.  36,  April,  1906,  t .  185. 

§  Proportioning  by  voids  has  seemingly  been  proven  fallacious.  See  Techno- 
logic Paper  No.  58  of  the  U.  S,  Bureau  of  Standards,  p.  39. 


SYSTEMS  OF  WATERPROOFING 


79 


QUAK 


MUS  f  !Y   CONSISTENCY 


FIG.    21. — Appearance    of    Gravel    Concrete    of    Three    Consistencies.     (From 
United  States  Bureau  of  Standards  Technologic  Paper  No.  58.) 


80  WATERPROOFING  ENGINEERING 

(4)  Mixing  the  sand  and  stone  and  providing  such  a  proportion 
of  cement  that  the  paste  will  slightly  more  than  fill  the  voids  in 
the  mixed  aggregate. 

(5)  Making  trial    mixtures  of  dry  materials  in   different  pro- 
portions to  determine  the  mixture  giving  the  smallest  percentage  of 
voids,  and  then  adding  an  arbitrary  percentage  of  cement,  or  else 
one  based  on  the  voids  in  the  mixed  aggregate. 

(6)  Mixing   the   aggregate   and   cement   according   to   a   given 
mechanical  analysis  curve.     (See  Appendix  I.) 

(7)  Making  volumetric  tests  or  trial  mixtures  of  concrete  with 
a  given  percentage  of  cement  and  different  aggregates,  and  selecting 
the   mixture   producing   the   smallest   volume   of   concretes;    then 
varying  the  proportions  thus  found,  by  inspection  of  the  concrete 
in  the  field. 

The  two  most  practical  methods,  however,  for  accurately  deter- 
mining the  proportions  of  each  material  is  by  mechanical  analysis 
of  the  aggregates  and  volumetric  synthesis,  or  proportioning  by 
trial  mixtures.  The  method  of  proportioning  concrete  according  to 
Fuller's  curve  gives  1  I  1.41  :  4.34  as  an  ideal  mix  for  producing  the 
densest  concrete. 

From  the  above  methods  of  proportioning  the  following  laws, 
which  relate  especially  to  the  grading  of  the  aggregate,  have  been 
evolved : 

1.  Aggregates  in   which   particles  have   been   specially  graded 
in  sizes  so  as  to  give,  when  water  and  cement  are  added,  an  artificial 
mixture  of  greatest  density,   produce  concrete  of  higher  strength 
than  mixtures  of  cement  and  natural  materials  in  similar  proportions. 

2.  The  strength  and  density  of  concrete  is  affected  but  slightly, 
if  at  all,  by  decreasing  the  quantity  of  the  medium  size  stone  of  the 
aggregate  and  increasing  the  quantity  of  the  coarsest  stone.     An 
excess  of  stone  of  medium  size,  on  the  other  hand,  appreciably 
decreases  the  density  and  strength  of  the  concrete. 

3.  The  strength  and  density  of  concrete  are  affected  by  the 
variation  in  the  diameter  of  the  particles  of  sand  more  than  by 
variation  in  the  diameters  of  the  stone  particles. 

4.  An  excess  of  fine  or  medium  sand  decreases  the  density  and 
also  the  strength  of  the  concrete,  as  will  also  a  deficiency  of  fine 
grains  of  sand  in  a  lean  concrete. 

5.  The  substitution  of  cement  for  fine  sand  does  not  affect  the 
density  of  the  mixture. 

6.  In  ordinary  proportioning  with  a  given  sand  and  stone  and 
a  given  percentage  of  cement,  the  densest  and  strongest  mixture  is 


SYSTEMS  OF  WATERPROOFING  81 

attained  when  the  volume  of  the  mixture  of  sand,  cement  and  water 
is  so  small  as  just  to  fill  the  voids  in  the  stone.  In  other  words,  in 
practical  construction,  use  as  small  a  proportion  •  of  sand  and  as 
large  a  proportion  of  stone  as  is  possible  without  producing  visible 
voids  in  the  concrete. 

7.  The  best  mixture  of  cement  arid  aggregate  has  a  mechanical 
curve  resembling  a  parabola,  which  is  a  combination  of  a  curve 
approaching  an  ellipse  for  the  sand  portion  and  a  tangent  straight 
line  'for  the  stone  portion. 

Grade  of  Workmanship  and  Supervision  Necessary  for  Water- 
tight Concrete.  The  third  requirement  is  careful  workmanship  and 
supervision,  particularly  the  latter,  for  obviously,  where  the  engineers' 
directions  are  not  followed,  or  orders  are  neglected;  where  supervi- 
sion or  inspection  is  lax,  little  can  be  done  in  the  way  of  making 
dense  concrete,  in  spite  of  willing  and  conscientious  help.  In  this 
connection  it  is  also  well  to  remember  that  when  inexperienced 
laborers  or  foremen  are  depended  on  to  produce  an  impervious 
concrete,  no  scientific  proportioning  or  prolonged  mixing  will  turn 
the  doubtful  balance  in  favor  of  the  concrete.  To  produce  impervious 
concrete  it  is  imperative  to  give  strict  supervision  to  details,  and 
this  phase  is  usually  neglected  by  inexperienced  labor.  To  accom- 
plish these  various  objects,  alert  foremen  and  experienced  workmen 
should  be  selected,  and  details  of  design  and  construction  carefully 
attended  to. 

From  the  foregoing  articles  it  may  be  seen  that  a  1  :  2  :  4  con- 
crete is  for  all  practical  purposes  impermeable,  and  that  with  scientific 
proportioning  of  ingredients  and  grading  of  aggregates,  as  outlined 
above,  a  1  :  3  :  7  concrete  can  be  made  almost  equally  impervious. 
Further,  the  maximum  density  of  concrete  is  obtained  when  the 
particles  lay  as  close  together  as  possible.  Consequently  its  imper- 
viousness  depends  upon  the  varying  degree  of  roughness  of  the 
stone  and  sand,  the  relative  sizes  of  stone,  sand  and  cement,  the 
proportionate  quantities  of  the  various  sizes,  the  readiness  with 
which  the  materials  compact,  and  the  amount  of  water  used.  The 
sizes  and  quantities  being  determined  and  adhered  to,  careful  work- 
manship and  cautious  supervision  will  do  the  rest. 

The  use  of  these  ingredients  according  to  the  varied  but  specific 
methods  outlined,  in  no  way  alters  the  present  standard  methods  of 
mixing  and  laying  concrete.  A  variation  though,  in  the  general 
method  of  mixing  concrete  by  machine  must  be  noted  because  of 
its  successful  accomplishment  in  the  matter  of  producing  dense  and 
impervious  concrete.  Contrary  to  the  prevalent  adverse  opinion 


82  WATERPROOFING   ENGINEERING 

of  the  practice  of  mixing  concrete  by  first  turning  on  the  water  and 
then  dumping  the  aggregate  into  the  mixer,  this  practice,  slightly 
modified  in  that  each  material  is  put  into  the  drum  separately, 
starting  with  the  water,  followed  by  the  cement,  the  sand,  and 
finally  the  large  aggregate,  the  drum  revolving  continuously,  actually 
produces  very  impervious  concrete.  This  practice  is  now  resorted 
to  in  the  manufacture  of  reinforced  concrete  water  pipe. 

Wherever  the  three  essential  requirements  can  be  fulfilled  and 
the  suggestions  for  making  them  effective  followed,  there  is  but 
little  need  to  add  any  waterproofing  compound,  providing  the  struc- 
ture is  not  subject  to  vibration  and  other  harmful  physical  influences. 
If  it  is  subject  to  such  influences,  then  the  only  systems  well  adapted 
for  the  waterproofing,  especially  on  large  engineering  structures, 
under  these  conditions,  are  the  membranous  or  sheet  mastic  sys- 
tems, or,  possibly,  the  surface  coating  system  and  in  some  cases,  the 
grouting  process.  However,  by  the  judicious  arrangement  and 
distribution  of  well-made  and  watertight  expansion  joints,  all  water- 
proofing may  sometimes  be  eliminated,  even  in  the  non-rigid  type  of 
structure. 

The  general  subject  of  the  self-densification  of  mortar  and  con- 
crete is  treated  exhaustively  in  standard  works  on  concrete,  and 
for  more  particular  and  detailed  information,  these  may  be  con- 
sulted to  good  advantage. 

GROUTING  PROCESS  OF  WATERPROOFING 

Definition,  Purpose  and  Development.  Waterproofing  by  the 
grouting  process  means  the  placing  (usually)  of  a  very  wet  cement 
mortar  behind  and  around  a  finished  iron  or  masonry  tunnel  or  other 
underground  structure,  injected  through  the  walls  or  some  portion 
of  its  body.  The  mortar  or  grout  is  forced,  generally  by  means 
of  a  pneumatic  grouting  machine,  through  cracks,  joints,  or  pipes 
suitably  located  in  the  structure,  until  refusal,  or  until  there  is 
evidence  of  the  grout  having  filled  all  the  seams  in  the  rock,  or  per- 
meated the  ground  in  the  immediate  vicinity  of  the  structure.  The 
purpose  of  this  is  to  force  the  ground  water  to  find  or  make  new 
channels  for  itself,  so  that  it  will  not  come  in  direct  contact  with  the 
structure,  which  may  not  be  sufficiently  watertight  in  itself  to  prevent 
seepage.  The  mortar  or  grout  is,  of  course,  in  itself  very  impervious. 
This  follows  from  the  richness  of  the  mixtures  used,  in  many  instances 
being  nothing  more  than  a  neat  cement.  In  fact,  such  mixtures, 
that  is,  either  neat  cement,  grout,  or  mortar,  form  the  most  imper- 


SYSTEMS  OF  WATERPROOFING  83 

vious  materials,  and  constitute  the  best  waterproofing  mediums  if 
applied  in  the  proper  place  and  manner.  For  the  grouting  process, 
these  materials  are  well  adapted,  and  serve  their  purpose  admirably. 

This  system  or  process  of  waterproofing  is  well  adapted  for  solidi- 
fying masonry,  various  soils  *  and  fissured  rock,  for  sinking  wet  con- 
struction shafts,  and  for  driving  tunnels  in  unstable  and  water- 
bearing material,  for  cutoff  walls  and  in  general  where  great  water 
pressures  are  to  be  resisted  by  the  finished  structure  as,  for  instance, 
around  tunnels  underneath  river  beds.  Grout  is  also  used  in  tunnel 
headings  which  must  pass  through  water-bearing  ground,  to  fill 
the  voids  in  the  dry  packing  over  a  tunnel  arch  or  elsewhere,  to 
cut  off  heavy  flows  of  water  from  cracks,  seams,  and  fissures  in  the 
rock  about  the  tunnel  or  its  shafts,  in  the  solidification  of  rock  and 
quicksand  at  dam  sites,  and  to  insure  a  watertight  contact  with, 
and  the  complete  protection  of,  steel  work  imbedded  in  the  masonry. 
In  fact  the  grouting  process  has  a  wider  field  of  usefulness  than  is 
generally  known. 

The  grouting  process  originated  or  was  invented  before  18P1,  but 
was  only  patented  in  that  year.  The  inventor,  Mr.  Robert  L. 
Harris,  set  forth  many  of  the  possibilities  of  this  process,  and  to-day 
it  is  a  recognized  engineering  procedure  and  is  used  on  practically 
all  tunnel  construction,  though  somewhat  modified  in  method. 
One  of  these  modifications,  perhaps  the  most  radical  and  of  very 
recent  origin,  consists  of  a  pneumatic  concrete  machine  that  mixes, 
conveys  and  places  the  concrete  in  one  continuous  stream  and 
operation,  producing  a  reasonably  dense,  and  impervious  concrete. 
This  process  eliminates  dry  packing  over  arches  of  tunnels,  permits 
the  placing  of  the  complete  ring  of  tunnel  or  lining  but  does  not 
readily  fill  up  seams  or  fissures  in  the  natural  rock.  This  particular 
apparatus  is  still  undergoing  improvement  and  promises  fair  to  be  a 
most  important  addition  to  the  engineer's  equipment  of  machines 
for  making  and  placing  dense  mortar  and  concrete.  The  grouting 
process  in  general  will  have  a  wider  field  of  usefulness  when  its 
operation  and  manipulation,  its  simplicity  and  effectiveness  are 
better  understood,  and  the  apparatus  perfected,  resulting  also  in 
greater  economy  in  its  application. 

*  In  sinking  a  large  steel  caisson  shaft  for  constructing  a  tunnel  under  the 
East  River  to  connect  the  new  subways  between  Brooklyn  and  Manhattan, 
New  York  City,  the  bulkheads  of  the  caisson  contained  a  number  of  2^-inch 
diameter  openings,  capped  during  sinking,  and  used  for  consolidating  the  sur- 
rounding material  by  grouting.  Public  Service  Record,  Vol.  3,  No.  3,  March, 
1916.  Published  by  the  Public  Service  Commission,  1st  District,  State  of  New 
York. 


84  .  WATERPROOFING  ENGINEERING 

Application  of  Grout  for  Waterproofing.  To  secure  good  results 
from  the  grouting  process,  great  care  must  be  exercised  in  conducting 
the  work.  This  work  is  most  advantageously  carried  on  at  a  rea- 
sonably low  temperature.  Attention  to  details  and  a  thorough 
understanding  of  the  nature  of  the  problem  at  hand  are  necessary. 
In  the  case  of  driven  tunnels,  for  instance,  great  judgment  and  care 
are  required  in  panning  off  running  water  so  that  none  of  it  will  come 
in  contact  with  fresh  concrete;  and  such  considerations  as  the  best 
method  of  drilling  and  placing  holes  for  grouting,  the  proper  con- 
sistency of  the  grout  mixture,  the  best  cement  to  use,  what  injection 
pressure  should  be  applied,  the  best  means  of  producing  and  control- 
ling the  flow  of  grout,  are  matters  vital  to  the  success  of  the  process. 
But  these  are  not  difficult  to  determine  as  a  rule  by  the  performance 
of  a  few  preliminary  field  tests. 

In  tunnels  grouting  under  pressure  is  not  done  until  some  time 
after  placing  the  complete  ring  of  masonry  lining  at  the  location 
to  be  grouted,  except  to  reduce  leakage  in  wet  ground,  or  in  connec- 
tion with  sections  of  masonry  lining  built  to  control  such  leakage 
or  to  support  wet  and  heavy  ground.  Generally,  grout  is  mixed 
as  thick  as  can,  with  certainty,  be  made  to  completely  fill  the  voids. 
Good  proportions  for  grout  are  1  :  1  (or  1-|)  :  1.  Sand  or  stone  dust 
and  either  Portland  or  natural  cement  can  be  used  to  equal  advantage. 
Grouting  should  be  carried  on  continuously  at  any  particular  seam 
or  void  until  completed,  without  intermission  sufficient  to  allow 
the  grout  to  take  an  initial  set.  The  grout  should  be  delivered  uni- 
formly and  steadily  to  avoid  occluding  air  in  the  interstices  of  the 
dry  packing.  This  is  usually  accomplished  by  using  two  grouting 
machines  so  that  while  one  is  shooting  grout  the  other  is  being 
charged.  This  is  especially  necessary  where  large  seams  or  voids 
in  rock  are  to  be  grouted. 

For  filling  large  voids  thick  grout  is  best,  but  for  small  cracks 
and  fine  seams  a  thin  mixture  should  be  used,  as,  for  instance,  a 
mixture  so  lean  that  the  water  will  carry  the  cement  as  far  as  possible 
into  the  fine  seam  and  so  avoid  blocking  up  close  to  the  drill  hole. 

In  tunnels  through  rock,  all  voids  over  the  arch  should  be  filled 
without  requiring  the  grout  to  travel  a  great  distance,  not  more  than 
25  feet  after  leaving  the  grout  pipe.  Grouting  of  any  section  of 
tunnel  should  begin  at  the  bottom  and  proceed  uniformly  upward, 
unless  some  other  order  is  found  more  desirable.  If  the  upper  ends 
of  each  series  of  grout  pipes  are  at  different  elevations,  the  grouting 
should  invariably  begin  at  the  lowest  pipes,  and  no  higher  pipe  con- 
nected until  the  grout  from  a  lower  pipe  begins  to  flow  out  of  it  (see 


SYSTEMS  OF  WATERPROOFING 


85 


Figs.  22  and  134).  Cutoff  walls  of  masonry  are  sometimes  built 
tight  against  the  roof  and  across  the  arch  of  the  tunnel,  dividing 
the  space  above  the  arch  into  sections.  This  makes  more  certain 
the  filling  of  the  voids  in  the  packing  of  that  section,  except  in  unsound 
rock  where  the  grout  can  flow  around  the  cutoff,  or  where  the  cutoff 
has  not  been  properly  made. 

Grouting  is  usually  considered  completed  when  no  more  grout 
can  be  forced  into  the  seam,  void  or  dry  packing  space  under  the 
required  pressure. 

Cement  and  Sand  for  Grouting.  Various  materials  are  sometimes 
found  effective  for  grouting  purposes.  For  instance,  muddy  water, 
liquefied  clay,  soft  clay,  and  ground  horse  manure  have  been  used 


FIG.    22. — Electric-driven    Compressor    Connected    to    Grout    Mixer,    Showing 
Arrangement  of  Equipment  and  Use  of  Grout  Pipe. 


alone  or  with  cement  for  sealing  fissures  in  rock  or  cracks  in  massive 
concrete.  But  grout  alone  is  usually  and  most  extensively  used  with 
marked  success  on  all  kinds  of  underground  structures,  success  de- 
pending, however,  on  the  care  and  attention  exercised  in  applying  it. 
Though  Portland  cement  is  the  most  commonly  used,  natural  cement 
may  be  used.  Sand  cement  is  also  used  and  is  found  very  efficient 
because  it  not  only  sets  as  well  as  Portland  cement  but  seems  to 
mix  better  and  produce  a  smoother  flowing  grout.*  However,  almost 
any  standard  commercial  but  preferably  quick-setting  cement  is 
suitable  for  grouting. 

The  best  sand  for  grout  is  that  grade  which  will  pass  approxi- 
mately 100  per  cent  through  a  sieve  having  64  openings  per  square 
inch  and  approximately  45  per  cent  pass  through  a  sieve  having 

*  Engineering  News-Record,  Vol.  78,  No.  13,  p.  627.     1917. 


86  WATERPROOFING  ENGINEERING 

1600  openings  per  square  inch.  If  it  is  desired  to  use  stone  screenings 
instead  of  sand  it  should  be  the  finest  obtainable  or  such  as  will  pass 
at  least  60  per  cent  through  an  8-mesh  sieve,  85  per  cent  retained  on 
a  50-mesh  sieve  and  90  per  cent  retained  on  a  100-mesh  sieve.  The 
quantity  of  water  necessary  to  form  the  mixture  depends  on  the 
physical  condition  of  the  ground,  rock  or  masonry  to  be  grouted  as 
well  as  upon  the  condition  of  the  sand  or  stone  screenings.  It  is 
always  best  to  commence  with  a  very  liquid  mixture,  say  one  part  of 
cement  to  five  or  seven  parts  of  water,  by  volume,  increasing  the 
amount  of  cement  untill  a  3  :  6  to  3  :  7  (sand  :  water)  mixture  is 
obtained.  But  it  is  not  possible  to  adhere  to  any  set  rule  in 
grouting,  therefore  the  operator  should  possess  both  judgment 
and  experience  if  the  greatest  efficiency  and  economy  are  looked 
for. 

Equipment  for  Grouting  Process.*  The  best  equipment  to  use 
for  forcing  grout  into  the  spaces  to  be  filled  depends  upon  the  pres- 
sure necessary  to  make  the  grout  travel,  and  the  consistency  of  the 
mixture  best  adapted  to  the  size  and  kind  of  voids  to  be  filled.  If 
a  considerable  yardage  of  grout  is  required  a  large  capacity  equip- 
ment is  best,  but  where  a  small  quantity  is  to  be  placed,  especially 
under  high  pressure,  a  different  equipment  is  necessary  to  secure 
the  best  results.  In  the  past,  and  to  a  certain  extent  at  present, 
grouting  has  been  done  by  pouring  the  mortar  or  grout  through  pipes 
arranged  in  such  a  way  as  to  secure  the  necessary  pressure.  Gener- 
ally, however,  more  pressure  than  that  afforded  by  the  head  of  grout 
alone  is  required. 

The  equipments  ordinarily  used  at  the  present  time  are  as  follows : 
(1)  Reciprocating  pumps  furnishing  a  continuous  flow  with  inde- 
pendent means  of  mixing  the  grout;  (2)  Pneumatic  mixers  and 
placers,  which  are  of  two  classes f- (a)  paddle  mixing  and  air  ejecting, 
(6)  air  mixing  and  air  ejecting;  (3)  paddle  mixing  and  water  ejecting. 
A  paddle  mixing  and  air  ejecting  type  of  grout  tank  has  been  exten- 
sively used  on  shield-driven  tunnels.  This  type  is  well  adapted  for 
placing  large  quantities  of  grout,  as  in*  grouting  dry  packing  behind 
tunnel  linings,  especially  over  the  arch. 

A  tank  of  the  air-mixing  and  ejecting  type  was  used  very  largely 
on  the  work  of  the  New  York  Board  of  Water  Supply,  particularly 
in  grouting  shafts  and  pressure  tunnels.  To  counteract  the  extremely 
high  head  over  the  Hudson  crossing,  a  Cameron  pump  was  used  to 
force  water  into  the  grout  tank.  This  raised  the  pressure  as  high 

*  Engineering  News,  May  6,  1916,  Vol.  75. 

f  Developed  and  patented  by  William  Lester  Canniff  in  1907. 


SYSTEMS  OF  WATERPROOFING  87 

as  600  pounds  per  square  inch,  which  was  sufficient  to  force  the 
grout  in  against  the  external  head. 

Great  care  must  be  exercised  in  the  manipulation  of  these  types 
of  grout  mixers  as,  for  instance,  to  shut  off  the  discharge  valve  the 
instant  the  last  bit  of  grout  leaves  the  tank;  otherwise  an  afterblast 
of  air  follows,  which  stirs  up  the  grout,  air  collects  in  the  spaces 
to  be  filled  by  the  grout  and  is  displaced  only  with  great  difficulty. 

The  paddle-mixing  and  water-ejecting  type  of  grouting  machine* 
is  a  newly  invented  modification  of  the  ordinary  grout  mixer.  This 
water-ejecting  type  seems  better  suited  than  the  air-ejecting  types, 
when  great  pressure  is  required,  to  accomplish  the  ejecting  process 
against  a  great  head.  This  water-ejecting  grout  machine  can  be 
and  is  also  used  for  low  heads  with  ordinary  pressures.  Its  main 
object,  however,  is  to  provide  an  inelastic  driving  power,  formed  by 
a  fluid  (water)  piston,  for  forcing  out  the  grout.  As  built,  this 
machine  is  more  easily  and  certainly  controlled  and  dispenses  with 
air  compression  when  water  under  a  head  is  available.  Its  limited 
use  does  not  yet  permit  a  statement  of  its  relative  efficiency  when 
compared  to  the  air-using  mixers. 

The  following  description  of  the  equipment  employed  in  grouting 
the  City  Tunnel  (Manhattan)  of  the  Catskill  Aqueduct  is  partic- 
ularly interesting  because  it  was  evolved  there  and  used  with 
remarkable  success.  It  is  in  fact  a  typical  equipment  for  all  deep 
tunnel  grouting.  Figs.  22  and  23  show  the  arrangement  of  the  plant 
commonly  used  on  the  Catskill  Aqueduct,  and  which  was  adopted 
in  some  sections  of  the  City  Tunnel.  Air,  piped  from  the  compressor 
plant  on  the  surface,  was  delivered  directly  to  the  grout  tanks  at  a 
pressure  of  from  80  to  100  pounds  per  square  inch  for  the  low-pressure 
work.  When  the  grouting  required  higher  pressure  the  air  was 
further  compressed  to  200  or  300  pounds  per  square  inch  by  means 
of  an  auxiliary  air-driven  compressor  or  "  booster,"  supplied  from 
the  compressor  at  the  surface.  Fig.  22  shows  a  type  of  equipment 
in  which  the  low-pressure  grouting  was  carried  on  as  usual  with  the 
air  furnished  from  the  surface  compressor  plant.  The  high-pressure 
grouting  was  also  done  with  a  small  compressor  driven  from  the  light- 
ing or  power  circuits.  With  a  plant  as  shown  in  Fig.  23,  both  the  low- 
and  high-pressure  grouting  was  done  with  the  electrically  driven 
compressor  in  the  tunnel.  The  adoption  of  this  equipment,  in  which 
the  compressor  in  the  tunnel  is  operated  only  when  grouting  is 
actually  being  done,  makes  unnecessary  the  more  or  less  continuous 
operation  of  the  large  compressor  plant  on  the  surface  and  effects  a 
*  Patented  by  S.  C.  Hulse,  February.  1917. 


88 


WATERPROOFING  ENGINEERING 


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SYSTEMS  OF  WATERPROOFING  89 

further  economy  in  avoiding  the  piping  of  compressed  air  through 
the  tunnel  for  grouting  work. 

Many  good  details  of  operation  and  experience  with  the  grouting 
process  are  described  in  a  series  of  articles  by  Mr.  James  F.  Sanborn,* 
Division  Engineer,  Board  of  Water  Supply,  New  York,  which  are  well 
worth  persual  by  readers  contemplating  similar  work. 

Steam-pressure  Concrete  Mixing  and  Placing  Machine.  A  new 
machine  embodying  the  principles  of  both  the  grout  mixer  and 
cement  gun  has  recently  been  developed  and  used  for  making  water- 
tight concrete  direct  by  materially  increasing  its  density  during 
placing.  This  machine  is  called  a  concrete  atomizer  and  the  details 
of  its  operation  are  as  follows :  f 

The  machine  illustrated  in  Fig.  24,  A,  can  make  concrete  weigh- 
ing about  170  pounds  per  cubic  foot.  Superheated  steam  at  from 
75  to  80  pounds  pressure  is  turned  into  the  mixing  chamber  while 
the  concrete  is  being  thoroughly  mixed  by  mechanical  means.  The 
mixture  is  then  discharged  through  an  outlet,  and  a  fresh  supply  of 
superheated  steam  takes  it  to  the  form  at  high  velocity  through  a 
special  hose,  which  is  provided  with  a  nozzle  opening  which  can  be 
instantly  increased  to  the  diameter  of  the  hose  in  case  it  is  plugged. 
Where  conditions  prevent  the  use  of  steam,  superheated  compressed 
air  gives  almost  as  good  results.  Fig.  24,  B,  shows  a  plant  where 
high-pressure  steam  is  supplied  from  a  locomotive,  passed  through  a 
reducing  valve,  and  superheated  to  supply  the  mixer.  The  super- 
heating effectively  prevents  condensation  of  water  in  the  stream  of 
concrete  being  delivered  from  the  nozzle  to  the  point  of  work,  and 
enables  the  workman  to  see  the  face  upon  which  he  is  playing  the 
stream. 

The  pressure  and  superheating  produce  a  concrete  of  considerably 
increased  strength,  while  the  force  with  which  the  mixture  is  applied 
gives  it  great  density.  A  thin  slab  placed  in  this  way  has  been  found 
to  be  waterproofed  under  high  water  pressure.  When  the  amount 
of  mixing  water  is  properly  regulated  little  aggregate  is  lost  by  falling 
from  the  working  face,  and  sections  1  foot  in  thickness  have  been 
placed  in  continuous  operation  on  vertical  walls.  One  of  the  photo- 
graphs shows  this  machine  at  work  repairing  a  concrete  retaining 
wall.  It  has  also  recently  been  successfully  employed  to  reline  a 
badly  leaking  tunnel  with  gravel  concrete  about  5  inches  thick,  t 

*  "  Grouting,  an  Effective  Remedy  for  Stopping  Leakage  in  Tunnels  and 
Shafts,"  Engineering  Record,  April  15,  22,  and  29,  1916. 

t  Invented  and  described  by  Harold  P.  Brown  in  Journal  of  American  Con- 
crete Institute,  Vol.  Ill,  No.  7,  July,  1915. 

I  Proceedings  American  Concrete  Institute,  Vol.  12,  1916. 


90 


WATERPROOFING  ENGINEERING 


FIG.  24. 

A.  "Concrete  Atomizer,"  which  Turns  Out  Concrete  under  80-lb.  Steam 
Pressure. 

B.  Mixer  Outfit   at   Work   on    Delaware,    Lackawanna  &   Western   R.  R. 
Retaining  Wall,  Newark,  N.  J. 


CHAPTER  III 
IMPERVIOUS  ROOFING 

Impervious  Roofing  Defined.  The  subject  of  impervious  roofing 
is  vast  and  complex,  and  we  can  only  hope  to  cover  its  more  general 
aspects  with  as  much  detail  as  is  consistent  with  the  practical  limits 
desired  for  this  chapter.  The  term  "  Impervious  Roofing  "  is  taken 
to  mean  those  materials  which  are  used  as  a  topmost  covering  for 
any  form  of  building  construction  and  whose  main  function  is  to 
create  a  watertight  roof.  These  materials  always  require  properly 
constructed  supports  regardless  of  the  character  of  the  roofing  or 
structure.  Impervious  roofing,  however,  does  not  include  the  sup- 
ports, such  as  trusses,  beams,  purlins  and  rafters,  but  does  include 
everything  else  such  as  sheathing  boards,  masonry  tiles  and  slabs 
or  other  suitable  sheathing  materials,  which  are  placed  upon  the 
roof  supports  for  the  double  purpose  of  providing  a  uniform  and 
continuous  surface  for  receiving  the  waterproofing  materials  and 
adding  to  the  protection  of  the  interior  from  the  elements.  Rain, 
hafl  and  snow  are,  of  course,  the  particular  scourges  which  create  the 
necessity  for  making  roofs  absolutely  watertight.  The  cost  of  roof- 
ing depends  on  so  many  different  factors,  that  no  worth-while 
estimate  could  be  given  as  a  general  indication  of  the  relative  saving 
to  be  expected  from  the  use  of  the  types  explained  below.  However, 
one  thing  should  be  borne  in  mind,  namely,  the  annoyance  and 
maintenance  expense  occasioned  by  leaky  and  short-lived  roofs, 
are  hardly  compensated  for  by  any  possible  saving  in  first  cost. 
The  following  considerations  should  guide  the  selection  of  a  roofing:* 
(1)  Chance  of  leaks  due  to  character  of  construction;  (2)  Probable 
life,  including  chance  of  damage  by  the  elements  and  by  wear  from 
other  causes;  (3)  Fire-resisting  value;  (4)  Cost  of  maintenance; 
(5)  Cost  of  materials;  (6)  Cost  of  laying. 

The  simplest  form  of  roof  is  the  primitive  flat  roof  of  the  Orient 
made  with  cross  beams,  thatch,  and  a  heavy  layer  of  stamped  clay, 
which  made  the  roof  more  or  less  watertight.  In  central  Syria  and 

*  American  Railway  Engineering  and  Maintenance  of  Way  Association, 
Bulletin  No.  131,  January  19,  1911. 

91 


02  WATERPROOFING  ENGINEERING 

in  Egypt  important  buildings  were  roofed  with  beams  and"  made 
watertight  with  slabs  of  stone.  The  Greeks  used  mainly  low- 
pitched,  gabled  roofs  protected  with  tiles  of  marble  or  terra  cotta. 
The  Romans  were  the  first  to  use  domes  of  brick  or  concrete  covered 
with  cement  and  lead  sheeting  for  watertight  ness.  On  elaborate 
structures  the  roofs  were  covered  with  tiles  or  with  bronze  plates. 
In  the  mediaeval  cathedrals  the  roofs,  which  invariably  had  a  very 
steep  pitch,  were  for  the  first  time  in  history  sheathed  with  boards, 
then  covered  with  slate,  tiles,  sheet  copper  or  lead.  The  Italian 
classic  type  of  roof  was  made  nearly  flat;  and  this  type  now  pre- 
dominates in  tropical  and  subtropical  climates.  Steep  roofs  quite 
obviously  predominated  in  regions  of  much  rain  or  nnow,  as  in 
northern  countries,  and  continue  to  do  so.  Most  modern  roofings 
have  not  the  same  architectural  beauty  as  those  of  ancient  classic 
types,  but  they  are  more  economical  and  efficient,  also  more  varied 
and  numerous  in  material  and  design  than  the  old  roofings.  Some 
of  the  more  important  ones  will  be  considered  separately  in  the 
following  articles. 

PROPERTIES  AND  APPLICATION  OF  SHINGLES 

Wood  Shingles.  For  securing  watertight  roofs,  many  materials 
are  now  in  common  use,  all  of  which  fall  under  four  general  heads  of 
roofing,  namely:  the  shingle  roof,  the  tin  roof,  the  felt  roof  (also 
called  the  composition  of  built-up  roof),  and  the  functional  roof. 
The  oldest  and  most  commonly  used^  of  these  roofings  is  the  shingle 
roof.  Wooden  shingles  are  universally  used  for  this  purpose.  These 
are  made  of  various  woods,  such  as  cypress,  redwood,  cedar,  juniper, 
white  pine  and  spruce;  this  also  being  the  order  of  their  durability. 
Cypress  is  the  most  durable  of  wood  shingles,  though,  as  with  all  other 
woods,  it  is  only  the  heartwood  that  shows  greatest  durability.* 
On  the  other  hand  redwood  is  much  less  inflammable  than  any  of  the 
others  and  spruce  is  the  cheapest.  Wooden  shingles  are  usually 
packed  in  bundles  (four  of  which  constitute  a  "  thousand,"  or  the 
equivalent  of  one  thousand  shingles  4  inches  wide)  sawed  to  dimension 
sizes,  which  range  from  4  to  6  inches  wide  and  16  to  24  inches  long, 
or  in  random  sizes,  which  range  from  2J  to  16  inches  wide  and  16 
to  24  inches  long.  Wood  shingles  are  easy  to  apply,  being  fastened 
to  the  sheathing  boards  with  two  or  three  nails  driven  into  the  part 
that  will  be  covered  by  the  exposed  portion  of  the  superimposed 

*  Cypress  shingles  were  laid  on  a  roof  of  a  building  in  Greenwich,  Conn.,  in 
1640  and  were  serving  well  250  years  afterwards. 


IMPERVIOUS  ROOFING  93 

shingle.  Unfortunately  it  is  almost  impossible  to  secure  nails  that 
will  not  corrode  before  good  shingles  will  deteriorate,  hence 
the  shingles  become  loosened  and  displaced.  The  use  of  pure 
iron  nails,  rather  than  galvanized  iron  nails,  will  reduce  this  hazard 
to  a  minimum.  No  shingle  should  show  more  than  one-third  of  its 
face  to  the  weather.  For  the  number  required  and  the  covering 
area  of  shingles,  see  Table  XXXVII.  For  protecting  wooden 
shingles  from  rapid  incineration  and  deterioration,  they  are  usually 
dipped  into  fireproof  liquids,  such  as  solutions  of  sodium  silicate  01' 
aluminum  sulphate,  or  coated  with  a  wash  mixture  composed  of 
lime,  salt  and  fine  sand  or  wood  ashes.  The  sodium  silicate,  however, 
is  readily  soluble  in  water  hence  it  will  wash  off  unless  the  shingles 
are  given  a  top  coat  of  oil  or  paint;  and  the  lime-salt-sand  solution 
will  not  stick  long  unless  also  covered  with  a  coat  of  oil  or  paint. 
The  most  effective  and  in  the  end  the  economical  way  would  be  to 
paint  the  shingles  with  a  zinc  borate  paint.  This  paint  is  also 
remarkably  fireproof.  For  preserving  purposes  such  salt  solutions  as 
zinc  chloride  and  sodium  fluoride;  or  such  oils  as  carbolineum  and 
dead  oil  (creosote  oil)  are  much  used.  The  shingles  are  dipped  in 
either  of  these  for  a  period  determined  by  experiment  but  usually 
depending  on  the  grade  of  wood  used.  If  creosote  oil  is  objection- 
able, then  besides  the  above  salt  solutions  a  solution  of  persulphate 
of  iron  of  2  to  2J  deg.  Baume",  can  be  substituted.  But  if  the  per- 
sulphate of  iron  solution  is  used  then  it  is  advisable  to  top  coat  the 
shingles  with  hot,  raw,  linseed  oil.  Often,  however,  besides  receiving 
preservative  treatment  the  shingles  are  painted  or  stained  to  create  a 
pleasing  effect.  Since  dipping  the  shingles  is  mainly  for  their  pres- 
ervation, they  are  completely  submerged  in  the  liquid,  but  in  paint- 
ing them,  which  is  mainly  for  appearance,  only  the  weather  portion 
of  the  shingles  is  coated.  However,  unless  this  is  done  with  the 
greatest  care,  it  would  be  better  to  paint  the  whole  shingle,  because 
otherwise  dry-rot  will  hardly  be  prevented.  For  shingles  that  are 
merely  to  be  stain-treated  (they  can  be  stained  almost  any  color), 
the  staining  is  best  and  most  durably  applied  by  dipping. 

Slate  Shingles.  Next  in  general  use  are  slate  shingles,  especially 
the  black  and  the  red  varieties,  but  various  shades  of  green  and  gray 
are  also  used.  These  are  supplied  commercially  in  thicknesses  of  J,  3^, 
and  J  inch,  increasing  by  |  inch,  to  1  inch.  Slate  should  be  hard 
and  tough,  and  have  a  well-defined  vein,  which  must  not  be  too 
coarse;  if  the  slate  is  too  soft,  it  will  absorb  moisture,  if  too  brittle, 
it  cannot  be  cut  and  punched  without  splitting,  and  it  will  easily  be 
damaged  by  walking  on  the  roof.  A  clear  metallic  ring  when  the 


94 


WATERPROOFING  ENGINEERING 


slate  is  struck  is  an  indication  of  its  soundness;  a  muffled  sound 
indicates  a  cracked  or  soft  condition.  For  the  number  of  shingles 
required  per  square  of  roof  surface,  see  Table  XXXVII.  Slate 
shingles  are  usually  attached  to  the  sheathing  over  two  or  more 
plies  of  treated  felt.  Sometimes  this  felt  membrane  is  cemented 
with  a  bituminous  binder.  Occasionally  the  slate  shingles  are  laid 
up  in  neat  cement,  or  rich  cement  mortar,  but  more  often  they  are 
nailed  to  the  sheathing  boards  like  wood  shingles  (see  Fig.  25).  On 
irregularly  shaped  roofs  and  in  locations  near  hips  and  valleys  and 
flashings  great  care  and  skill  are  required  in  laying  the  shingles  so 
as  to  avoid  leaks.  For  these  places  tin  is  often  used  but  copper  or 
sheet  lead  are  best  adapted  for  the  purpose. 


Gage 


FIG.  25.— Typical  Details  of  Slate  Roofing 


Slate  shingles  are  often  attached  to  concrete  or  porous  terra- 
cotta roofs,  by  being  nailed  directly  to  the  surfaces.  This  is  poor 
practice  especially  on  roofs  having  the  minimum  allowable  pitch. 
A  means  for  attaching  them  more  securely  is  to  nail  1}  by  2  inch- 
wood  strips  to  the  outer  face  of  the  concrete  or  terra  cotta,  the 
strips  being  set  the  proper  distance  apart  to  receive  the  slate 
shingles,  and  then  plastering  between  the  strips  with  cement  mortar. 
This  gives  a  good  nailing  base  for  the  roofing.  Among  the  best 
impervious  roofings  that  can  be  put  on  a  flat  or  moderately  inclined 
roof  is  one  of  slate  shingles,  laid  over  a  membrane  of  five  plies  of 
treated  felt.  The  membrane  is  applied  with  bituminous  binder  as 
for  a  felt  roof,  and  the  slates  bedded  on  the  membrane  in  cement 


IMPERVIOUS  ROOFING  95 

mortar.*    For  this  arrangement  the  shingles/ are  thicker  than  ordi- 
nary and  laid  butt-joint  fashion. 

Tile  Shingles.  Next  in  order  of  usage  are  tile  shingles.  Clay 
tiles  were  used  before  historic  times,  and,  of  course,  all  down  the 
ages  there  has  been  considerable  improvement  in  the  product.  Not, 
however,  till  1851,  when  the  first  tile-making  machine  was  invented, 
did  the  manufacture  of  clay  tiles  assume  a  real  industrial  aspect, 
as  previously  all  tiles  were  made  by  hand.  To-day  the  tile  industry 
is  extensive  and  exists  practically  in  all  countries  of  the  world. 
Tiles  are  manufactured  in  various  sizes  and  forms  and  of  such 
materials  as  clay,  shale  (vitrified  tiles),  cement  mortar,  and  even 
reinforced  concrete.  (See  Figs.  27,  28,  and  29.)  Clay  roofing  tiles 
properly  made,  that  is,  well-glazed  and  hard-burned  throughout, 
cannot  be  excelled  for  durability.  The  application  of  vitrified  tiles 
often  depends  on  their  form.  Some  are  curved  on  both  ends  and 
hook  on  each  other  downward  from  the  ridge  tile,  which  is  straddled 
on  the  ridge  pole;  some  are  rectangular  (the  usual  dimensions  being 
1J  by  6  by  9  inches),  and  of  various  shades,  such  as  red,  black,  green 
and  gray.  It  is  harder  to  get  a  tight  roof  with  ordinary  tile  than 
with  slate,  but  the  interlocking  shapes  that  have  been  devised  give 
very  good  results  in  this  respect.  Sometimes  the  tile  is  imbedded 
in  a  plastic  cement  or  in  cement  mortar  upon  an  underlying  three- 
to  six-ply  built-up  felt  roof,  replacing  the  gravel.  In  fact,  this 
scheme  has  become  the  practice  for  roofs  of  modern  high  and  expen- 
sive buildings.  Flat  porous  tiles  similar  to  the  above,  but  of  larger 
size  are  usually  attached  in  the  same  manner  as  slate  shingles. 
Sometimes  the  large-size  tile  is  laid  directly  on  steel  or  wooden 
purlins,  which  must  be  spaced  to  suit  the  length  of  the  tile. 

The  cement  tiles  are  of  various  shapes  and  sizes;  those  shown  in 
Fig.  28  being  an  extensively  used  type.  They  are,  of  course,  fire- 
proof as  well  as  waterproof,  strong  and  practically  permanent. 
They  are  usually  made  so  as  to  lay  directly  on  the  purlins. 

The  reinforced  concrete  roofing  tiles  are  mostly  home  made,  so  to 
speak.  They  can  be  made  anywhere  in  all  sizes,  shapes  and  colors, 
hence  are  very  adaptable  for  special  purposes.  Reinforced  concrete 
roofing  tiles  were  extensively  used  on  nearly  all  superstructures  of 
the  New  York  Catskill  Aqueduct.  Because  of  their  relative  high 
cost  their  use  is  limited  to  elaborate  and  expensive  structures;  but 
because  of  their  permanence  and  serviceability  they  should  have  a 
wider  usage.  In  this  connection  the  following  brief  suggestions  for 
making  reinforced  concrete  tiles  will  be  of  material  aid. 

*  Kidder's  "  Architects  and  Builders  Pocket  Book,"  p.  567. 


96 


WATERPROOFING  ENGINEERING 


Success  in  using  reinforced  concrete  roofing  tiles  depends  on  the 
care  with  which  they  are  made,  handled  and  placed.  The  first 
requisite  is  that  they  be  made  impervious  to  water  and  as  dense 
and  strong  as  practicable.  The  thickness  of  tiles  varies  from  f  inch 
to  3  inches,  depending  on  appearance  and  extraneous  functions.  The 


FIG.  27.— Baked-clay  (Vitrified  Tile)  Roofing,  Showing  A,  Spanish;  B,  German; 
and  C,  Closed-shingle  Types. 

thickness  of  pan  (flat)  tiles  (as  used  on  the  above  mentioned  work*) 
except  at  the  ribs,  or  along  the  edges,  was  approximately  If  inches, 
being  nowhere  less  than  1  inch,  while  the  average  thickness  was  not 

*  New  York  Catskill  Water  Supply,  Type  "  A  "  Reinforced  Concrete  Roof 
Tiles. 


IMPERVIOUS  ROOFING  97 

to  exceed  1|  inches  (see  Fig.  29).  In  placing  the  tiles  upon  the  steel 
frames  of  the  roof  (and  steel  frames  are  preferably  used  for  their 
support  so  as  to  obtain  the  necessary  rigidity) ,  the  steel  should  be 
covered  with  mortar  or  other  suitable  coating  material  for  protection 
against  corrosion.  It  is  important  that  this  covering  be  neither 
chipped,  cracked  nor  otherwise  injured.  Flashings  for  tiles  about 


FIG.  28.— Types  of  Cement  Roofing  Tile. 

the  chimneys  should  preferably  be  of  sheet  copper,  such  as  weighs 
20  ounces  per  square  foot. 

The  best  aggregate  for  concrete  tiles  is  clean  quartz,  which  con- 
tains both  fine  and  coarse  particles  of  suitable  limiting  sizes  and  is 
satisfactorily  graded.  All  aggregates,  however,  should  not  contain 
sufficient  loam  or  clay,  or  other  objectionable  matter,  to  render  them 
unsuitable  for  making  an  impervious  and  uniformly  clean-looking 


98 


WATERPROOFING   ENGINEERING 


d 
I 

e 

1 

"S 
a 

1 

1 

1 

1 

B 

n3 

•s 

0 

Tiles  marked  "X" 

Slight  modificatioi 

tay  be  necessary. 

m 


IMPERVIOUS  ROOFING  99 

tile.  For  best  results  it  is  important  to  use  clean  water  and  to  form 
a  medium  consistency  concrete.  In  general  the  mixture  may  be 
approximately  in  the  proportions  of  1  :  2f  to  1  :  3,  the  aggregates 
being  measured  by  weight  or  volume,  as  found  practicable.  It  is 
important  to  thoroughly  mix  the  concrete  in  a  good  mechanical 
mixer,  except  that  very  small  quantities  may  be  mixed  by  hand. 
Concrete  mixing  by  machine  should  be  continued  for  at  least  ten 
minutes.  No  tiles  should  be  made  of  retempered  concrete.  Where 
it  is  desired  to  tint  the  tiles,  mineral  coloring  materials  may  be  added 
during  the  mixing,  but  if  the  bottom  surfaces  are  to  be  exposed 
inside  of  a  building  they  should  preferably  be  a  very  light  gray  or 
white.  The  top  surface  of  tiles  may  be  tinted  by  the  surface  applica- 
tion of  a  suitable  paint. 

Steel  reinforcement  for  concrete  tiles  should  be  ample,  pref- 
erably of  the  mesh  fabric  variety,  firmly  fastened  at  each  inter- 
section and  properly  placed.  For  reinforcing  the  ridge,  hip,  rib  and 
finial  tiles  or  other  special  shapes  and  the  bearing  lugs  of  pan  tiles, 
steel  rods  about  \  inch  in  diameter  will  be  very  useful  in  addition 
to  the  mesh  reinforcement.  The  best  practice  is  to  put  the  steel 
in  the  lower  part  of  the  tile  and  every  part  of  it  at  least  -f$  inch 
from  the  surface.  The  reinforcement  must  be  placed  in  exact 
positions  specified  by  design,  and  held  in  position  so  as  to  prevent 
displacement  while  the  concrete  is  being  deposited  and  while  it  is 
setting.  If  the  concrete  is  not  sufficiently  wet  to  thoroughly  coat 
the  steel  with  cement,  it  is  advisable  to  coat  the  steel  with  cement 
grout  as  it  is  being  placed  in  the  form  or  immediately  before 
placing. 

After  fabrication  the  tiles  should  be  seasoned;  that  is,  in  order 
to  avoid  all  manner  of  cracks,  the  tiles,  on  removal  from  the  forms, 
should,  during  the  first  month,  be  kept  constantly  moist.  It  is  very 
important  that  all  the  tiles  should  be  true  to  the  shapes  required 
by  the  particular  design;  especially  is  it  important  to  see  that  the 
flat  tiles  are  not  warped.  Particular  attention  is  also  necessary  for 
making  those  edges  which  bear  on  the  surfaces  of  other  tiles  so 
true  and  smooth  as  to  form  good  joints.  Variations  from  any 
dimension  ought  not  to  exceed  |  inch.  The  tiles  should  be  adjusted 
in  place  so  as  to  give  close  joints  where  exposed  to  the  weather,  and 
so  that  each  tile  will  have  a  satisfactory  bearing.  The  exposed 
spaces  between  the  soffits  of  the  eaves  tiles  and  the  cornices  should 
be  pointed  smooth  with  Portland  cement  mortar,  which  may  be 
made  to  match  the  tiles  in  color.  All  joints  should  be  made  per- 
manent with  an  elastic  roofing  cement.  Tiles  having  unevenness, 


100  WATERPROOFING  ENGINEERING 

voids  or  other  objectionable  imperfections  which  would  reduce  their 
impermeability,  should  not  be  used. 

To  test  the  permeability  of  concrete  tiles,  at  least  two  seasoned 
pan  tiles  should  be  placed  separately  in  a  horizontal  position,  top  up, 
and  subjected  over  the  area  which  would  be  exposed  in  the  roof,  to  a 
3-inch  depth  of  water  for  seven  consecutive  days,  after  which  a 
well-made  tile  should  not  show  any  dampness  over  the  bottom. 
The  strength  of  tiles  may  be  tested  by  placing  flatwise,  horizontally, 
top  up,  a  tile  not  less  than  twenty-eight  days  old,  on  rigid  supports, 
one  near  each  end  of  the  tile  and  extending  across  its  full  width. 
Thus  supported,  a  tile  as  illustrated  in  Fig.  29  should  be  able  to 
support  a  central  load  of  at  least  600  pounds,  applied  gradually, 
bearing  across  the  whole  width  of  the  tile. 

Prepared  Shingles.  Then  there  are  what,  for  want  of  a  better 
name,  are  called  "  Prepared  Shingles."*  Indeed,  these  shingles 
are  fast  becoming  a  very  staple  roofing  material.  Prepared  shingles 
are  composed  of  various  materials,  such  as  asbestos  fiber  compressed 
into  boards  of  various  thicknesses,  sizes  and  shapes :  or  of  two  or  three 
plies  of  wool  and  rag  felt,  saturated  and  coated  with  various  grades 
of  asphalt,  made,  smooth  or  rough-surfaced  and  cut  into  shingles  8  by 
12 J  inches  or  8  by  16  inches  which  are  the  two  standard  sizes;  or  of  a 
thick,  treated,  wool-felt,  surfaced  either  with  fine  sand  cr  carefully 
screened  grit,  but  sometimes  with  mica  flakes,  or  stone  screenings 
(see  Figs.  30  and  34)  such  as  slate,  feldspar  and  silicate,  whose  varied 
colors  create  pleasing  roof  effects.  In  the  felt  shingles,  it  is,  of 
course,  the  asphalt  (or  coal-tar  pitch)  treatments  which  give  the 
weather-resisting  qualities  to  them.  If  unsurfaced,  they  are  of  light 
weight  and  sometimes  the  asphalt-treated  shingles  tend  to  disin- 
tegrate or  the  coal-tar  pitch  hardens  and  the  shingles  become  brittle 
on  exposure.  Hence,  the  final  surfacing  with  a  layer  of  mineral 
matter  serves  a  threefold  purpose. 

In  view  of  the  growing  importance  of  prepared  shingles,  the 
following  instructions  for  applying  them  will  be  found  helpful : 

The  sheathing  boards  should  be  laid  closely  and  securely  nailed. 
It  is  necessary  to  see  that  the  surface  is  clean  and  free  of  all  pro- 
jecting nail  heads  or  other  obstructions.  On  particular  work,  it  is 
good  practice  to  first  cover  the  sheathing  boards  with  a  single  ply 
of  building  paper  or  treated  felt.  One  row  of  shingles  is  laid  length- 
wise along  the  entire  lower  edge  of  the  sheathing,  extending  J  inch 
over  the  edge  of  the  sheathing  or  inner  edge  of  the  gutter.  These 
must  fit  closely  and  each  lower  corner  nailed,  driving  the  nails  2 
*  Prepared  shingles  were  originated  in  1901  and  first  marketed  in  1910. 


IMPERVIOUS 


101 


inches  from  the  lower  edges  and  ends.  One  nail  is  driven  half  way 
between  the  two,  thus  using  three  nails  to  each  shingle  on  this  row. 
It  is  best  to  use  1-inch  galvanized  nails  with  large,  flat  heads  about 
\  inch  in  diameter. 

The  regular  course  should  begin  with  a  full-sized  shingle,  as  shown 
in  Fig.  30,  laying  same  parallel  to,  and  flush  with,  the  outer  edge  or 
vertical  end  of  the  roof.  The  lower  end  is  flushed  with  the  first  layer, 
allowing  J-mch  space  between  the  shingles.  The  course  is  thus 
continued,  using  two  nails  to  the  shingle,  driven  4|  inches  from  the 
lower  edge.  The  second  row  is  thus  begun  with  two-third-sized 


FIG.  30. — Undersurfaced,  Prepared-shingle  Roofing.     (A,  Nails.) 


shingles,  laid  4  inches  to  the  weather,  and  nailed  as  the  others.  The 
third  row  follows  with  one-third-sized  shingles  and  the  same  spacing, 
etc.  In  beginning  the  fourth  row,  full-sized  shingles  are  again  used 
and  continued  as  before.  The  J-inch  space  between  shingles  allows 
for  contraction  and  expansion  and  improves  the  general  appearance. 
If  shingles  are  laid  4  inches  to  the  weather  and  4|  inches  from 
the  lower  ends,  all  nail  heads  will  be  fully  covered  and  protected. 
Metal  should,  of  course,  be  used  for  all.  flashings  and  for  lining 
gutters. 

Asbestos  Shingles.*  There  are  on  the  market  various  brands  of 
pressed  asbestos  shingles  mostly  cut  to  a  standard  size,  usually 

*  Originated  in  Austria.     Patented  in  the  United  States  in  January,  1907. 


102 


ENGINEERING 


8  by  16  inches  (see  Fig.  31,  A)  which  are  in  demand  because  they 
are  both  fireproof  and  waterproof.  They  are  made  of  a  mixture  of 
asbestos  and  Portland  cement  and  compressed  to  any  desired  thick- 


FIG.  31. 

A.  The  American  or  Straight-laid  Method  of  Applying  Shingles. 

B.  The  Honeycomb  or  Hexagonal  Method  of  Laying  Square-cut  Shingles. 

C.  The  Diagonal  or  French  Method  of  Applying  Shingles. 

ness  under  hydraulic  pressure.  When  new,  they  absorb  between 
5  and  10  per  cent  by  weight  of  water,  depending  on  the  compression 
they  underwent.  But  when  exposed  to  the  air  for  any  length  of 
time,  further  hydration  of  the  cement  decreases  their  absorptiveness 


IMPERVIOUS  ROOFING  103 

and  increases  their  impermeability.  The  strength,  durability,  imper- 
meability and  fireproof  properties  of  asbestos  shingles  are  important 
factors  in  overbalancing  their  high  cost.  Asbestos  shingles  like  most 
others  are  also  made  in  special  sizes  and  forms  (see  Fig.  31,  B)  and 
sometimes  are  applied  in  the  same  manner  as  tile  or  slate  shingles. 
Sometimes  they  are  laid  up  in  proprietary  cements,  a  common 
cement  for  such  purpose  being  a  paste  made  of  China  wood  oil  and 
heavy  petroleum  residuum. 

There  are  three  standard  methods  for  applying  shingles  which 
will  be  described  briefly  in  connection  with  the  application  of  asbestos 
shingles,  although  these  methods  are  equally  applicable  to  other 
kinds  of  shingles.  These  are  the  American  method,  the  Hexagonal 
method  and  the  French  method.  But  regardless  of  the  method  of 
application  it  is  absolutely  necessary  that  all  asbestos  shingles  be 
very  hard  pressed,  only  slightly  absorbent,  reasonably  strong,  and 
cut  to  uniform  size  and  thickness  to  secure  the  best  results. 

American  Method  of  Applying  Asbestos  Shingles.  This  method 
has  many  modifications  of  application,  but  the  commonest  way  is 
as  follows: 

The  roof  boards  are  laid  so  as  to  break  joints  and  nailed  securely 
in  place,  leaving  no  loose  ends.  They  should  be  well-seasoned  and 
preferably  of  a  narrow  width.  One  ply  of  felt  is  laid  horizontally 
over  the  roof  boards  with  a  2-inch  lap,  and  with  6-inch  laps  on  hips 
and  valleys.  Furring  strips  J  to  \  inch  wide  are  laid  under  the  felt, 
parallel  to  and  flush  with  the  eaves,  and  then  one  course  of  shingles 
is  laid  at  eaves  lengthwise  and  parallel  to  same,  overhauling  the  eaves 
about  \  inch.  The  second  course  of  shingles  entirely  covers  the 
first  course  (see  Fig.  31,  A),  but  breaking  joints;  after  which  the 
process  is  the  same  as  with  wooden  shingles  or  slates,  exposing  not 
more  than  7  inches  to  the  weather  and  fastening  each  shingle  in 
place  with  at  least  two  galvanized  iron  roofing  nails.  Nails  must 
never  be  driven  down  tight;  it  is  only  necessary  to  drive  them 
firmly.  Over  the  ridges  and  hips  asbestos  ridge  and  hip  rolls  should 
be  applied  with  not  less  than  3-inch  laps,  fastened  in  place  with  ridge 
roll  fasteners.  Where  the  ridge  pole  does  not  project  high  enough 
above  the  roof  boards  to  allow  direct  application  of  the  ridge  roll,  it 
is  necessary  to  put  in  a  false  pole,  so  that  it  is  possible  to  get  a  direct 
fastening  through  the  top  of  the  ridge  roll  (see  Fig.  32) .  All  chimneys 
and  valleys  must  be  flashed  with  copper  or  other  suitable  metal. 

Hexagonal  and  French  Methods  of  Applying  Asbestos  Shingles. 
The  Hexagonal  method  for  applying  asbestos  shingles  is  as  follows : 

The  roof  is  prepared  as  in  the  American  method.     Furring  strips 


104 


WATERPROOFING  ENGINEERING 


i  to  \  inch  thick  by  1|  inches  wide  are  laid  underneath  the  felt 
parallel  to  and  flush  with  the  eaves.  Then  one  course  of  asbestos 
shingles  is  laid  end  to  end,  parallel  with  and  overhanging  the  eaves, 
not  less  than  J  inch;  over  which  is  applied  one  course  of  shingles 
entirely  covering  the  starter,  breaking  all  joints  (see  Fig.  31,  B). 
The  balance  of  the  roof  is  covered  with  shingles,  12  by  12  inches, 
laid  as  shown,  exposing  9f  by  9J  inches  to  the  weather.  All  shingles 
are  fastened  in  place  with  galvanized  nails,  but  the  points  of  the  main 
body  shingles  are  fastened  with  copper  storm  nails.  Here  also  the 
nails  must  not  be  driven  down  tight,  but  firmly.  All  the  main  body 
shingles  should  be  laid  with  the  diagonal  lines  on  a  45-degree  angle 
with  the  eaves.  Over  the  ridges  and  hips  asbestos  ridge  and  hip 
rolls  must  be  applied  in  the  same  way  as  for  the  American  method. 
In  applying  the  hexagonal  shingles  the  same  method  is  used  as  with 
the  rectangular  ones  of  the  American  method. 


FIG.  32. — Details  of  Ridge  Roll  Construction. 


The  French  method  is  illustrated  in  Fig.  31,  C,  which  is  quite 
self-explanatory. 

In  general,  shingles  of  all  materials  when  well  laid  make  a  hand- 
some and  watertight  roof,  and  are  easily  replaced  and  repaired. 
They  are  serviceable  on  all  but  flat  roofs,  except  as  noted  under 
slate  and  tile  shingles.  The  minimum  pitch  for  wooden  shingles, 
slates,  tile  (when  laid  as  roofing  proper)  and  prepared  shingles,  is 
one-third,  that  is,  1  foot  of  rise  for  each  3  feet  of  span.  Table  VIII 
gives  the  minimum  pitch  for  other  roofing  materials,  but  these 
values  may  vary  somewhat,  because  each  manufacturer  usually 
establishes  the  incline  upon  which  his  own  roofing  should  be  applied. 

In  connection  with  all  shingled  roofs,  sheet  lead  is  often  used 
for  gutters,  flashings,  etc.  The  weights  recommended  for  these 
purposes  are  as  follows: 

Gutters 7  pounds  lead  per  square  foot. 

Hips  and  ridges 6  pounds  lead  per  square  foot. 

Flashings 4  to  5  pounds  lead  per  square  foot. 


IMPERVIOUS  ROOFING  105 

Table  XXXV  gives  the  thickness  and  weight  of  sheet  lead. 
Where  sheet  lead  is  to  be  used  to  form  rather  large  hips  and  other 
important  parts  of  the  roof,  it  is  not  desirable  to  lay  it  in  greater 
lengths  than  10  or  12  feet  without  a  joint  roll  or  drip  to  allow  for 
movement  due  to  the  great  expansion  and  contraction  of  lead  from 
changes  of  temperature. 

TABLE  VIII.— MINIMUM  PITCH  OF  ROOFS 

Rise/Span 

Asphalt  composition 1/24 

Tin  (standing  seam) 1/8 

Tin  (flat  seams) 1/24 

Corrugated  iron 1/4 

Sheet  iron 1/4 

Copper ....1/6 

Lead 1/6 

Thatch ,. 1/2 

Shingles 1/3 

Slate 1/3 

Tiles,  terra-cotta 1/3 

Reinforced  concrete  slabs 1/24 

Ready  roofing 1/24 

Felt,  asphalt  (or  tar) ,  and  gravel  (or  slag)  (maximum)  1/4 


TIN  ROOFING 

Properties  and  Application  of  Tin  Roofing.  The  second  type  of 
roofing,  that  is,  tin  roofing,  is  applicable  to  both  flat  and  pitched 
roofs,  and  is  adaptable  to  special  and  difficult  conditions,  as  well 
as  practicable  in  every  climate.  Tin  plate  (which  consists  of  iron 
or  steel  sheeting,  tinned  with  an  alloy  of  lead  and  tin),  copper  and 
zinc  sheetings,  are  the  most  generally  used  for  this  purpose  and  their 
predominance  is  in  the  order  given.  The  coat  on  the  tin  plate  is, 
as  noted  above,  mostly  an  alloy  of  lead  and  tin  with  the  quantity 
of  lead  usually  predominating.  The  best  grade  of  tin  is  that  which 
is  coated  with  an  alloy  consisting  of  30  per  cent  pure  tin  and  70  per 
cent  pure  lead.  The  weight  of  this  coating  varies  between  8  pounds 
and  40  pounds  per  box  of  112  sheets,  14  by  20  inches,  depending  on 
the  thickness  of  the  coat.  Plates  carrying  less  than  20  pounds 
should  not  be  used  for  permanent  buildings ;  for  such  use  30  to  40- 
pound  coating  is  most  serviceable.  Where  the  coating  is  all  of 
lead  it  is  called  terne  plate  and  this  grade  is  generally  used  on  inex- 


106  WATERPROOFING  ENGINEERING 

pensive  roofs.  Tin  plates  usually  come  in  standard  sizes,  either 
14  by  20  inches,  or  20  by  28  inches,  with  prepared  edges  to  enable 
the  roofer  to  make  locked  seams  between  them  as  they  are  applied. 
A  modified  form  of  tin-plate  roofing  consists  of  rolls  of  tin  plates 
about  2  feet  wide  and  of  various  lengths  (between  10  and  50  feet)  as 
required.  These  strips  are  applied  by  unrolling,  joining  and  solder- 
ing them  into  a  continuous  sheet  over  the  entire  roof,  usually  with 
standing  seams.  Copper  and  zinc  sheeting  also  come  in  standard 
sizes  but  are  often  made  in  any  required  size  and  thickness  to  suit 
the  particular  conditions  of  the  roof. 

Tin  plates  for  flat  roofs  are  usually  put  on  with  the  ordinary 
flat-lock  joint,  the  sheets  of  tin  being  nailed  under  the  lock.  After 
the  sheets  are  nailed  and  hooked  together  the  hook  joints  are  beaten 
down  with  a  wooden  mallet  and  then  soldered. 

When  it  is  desired  to  make  some  allowance  for  contraction  and 
expansion  the  sheets  are  fastened  with  tin  clips  nailed  to  the  roof  as 
shown  at  A,  Fig.  33;  in  this  way  there  are  no  nails  through  the  sheets 
of  tin,  being  held  in  place  by  the  clips.  Fig.  33,  B,  shows  a  section 
of  this  joint.* 

To  allow  for  greater  ease  of  movement  due  to  expansion  and 
contraction  and  to  reduce  the  use  of  nails  and  soldering  of  joints  to  a 
minimum,  what  are  known  as  standing  seams  are  used.  These 
seams  are  always  placed  perpendicular  to  the  eaves,  but  not  carried 
into  the  gutter,  where  they  would  interfere  with  drainage  or  cause 
leaks  through  water  making  its  way  into  the  seams.  Standing-seam 
roofs  are  fastened  with  clips  nailed  to  the  sheathing  and  turned 
down  in  the  standing  seam.  Fig.  33  (C,  D,  E)  shows  a  standing- 
seam  roof  in  the  different  stages  of  construction. 

Fig.  33,  F,  shows  the  joint  turned  down  as  a  flat  lock  joint. 

In  standing-seam  roofs  or  any  roof  where  the  tin  is  laid  in  long 
lengths  the  cross-joints  should  be  double-locked;  this  is  shown  at 
G,  while  the  ordinary  single  lock  is  shown  at  H. 

Tin  roofs  are  sometimes  put  on  in  lengths  running  with  the  slope 
of  the  roof,  the  strips  of  tin  being  turned  up  and  laid  between 
strips  of  wood,  as  shown  at  J.  This  method  provides  ample  allow- 
ance for  expansion  and  contraction,  and  also  enhances  the  appearance 
of  the  roof. 

Fig.  33,  K,  shows  a  method  used  for  zinc  and  copper,  while  L 

shows  how  the  cross-joints  should  be  made  at  the  ends  of  the  sheet 

metal;   a  rise  or   step   is  made  in  the  roof  and  the  two  sheets  of 

metal  turned  and  locked  as  shown.     In  working  zinc  care  must  be 

*  Richey's  "  The  Building  Mechanics'  Ready  Reference." 


IMPERVIOUS  ROOFING 


107 


exercised  in  making  the  bends  and  angles,  for  if  they  are  made  too 
sharp  the  metal  is  liable  to  crack. 

Wherever  any  metal  roof  covering  finishes  at  a  wall  or  any  place 
where  flashing  is  necessary  the  roof  metal  should  be  turned  up  8  or 
10  inches  and  securely  fastened;  then  this  metal  should  be  counter- 


b 

H 

___r||_ 

=E=, 

Cleat 


SECTION  ab 


(Cleat  Omitted) 


flashed  and  the  flashing  let  into  the  joint  of  the  wall  at  least  2  inches 
and  well  cemented.  This  is  a  part  of  the  work  that  requires  partic- 
ular attention  so  as  to  get  everything  watertight. 

In  all  metal  roofing  the  main  points  are  to  get  the  joints  water- 
tight and  to  make  provision  for  expansion  and  contraction. 


108  WATERPROOFING  ENGINEERING 

*  % 

As  soon  as  the  roofing  is  in  place  and  the  joints  all  soldered,  it 
should  then  be  painted.  But  just  before  painting,  however,  the 
metal  roofing  should  be  gone  over  and  all  grease,  oil,  resin,  etc., 
removed  with  gasoline  or  benzene. 

Roofs  of  less  than  one-fifth  pitch  are  best  made  with  flat  seams 
well  locked  together.  The  sheets  of  tin  should  preferably  be  of  the 
small  size,  14  by  20  inches,  as  the  small  sheets  cause  more  seams  and 
make  a  stiff  roof  which  prevents  buckling.  Ordinarily,  nails  are 
driven  through  the  edge  of  the  sheet  under  the  lock,  but  in  good  work 
the  sheets  should  be  fastened  with  tin  clips  or  cleats  nailed  to  the 
roof.  This  leaves  the  tin  of  the  roof  free  to  expand  and  contract. 
Nails  or  cleats  should  be  used  about  every  6  or  7  inches.  In  solder- 
ing the  seams  rosin,  and  not  acid,  should  be  used,  as  the  latter  may 
attack  and  destroy  the  body  of  the  tin,  and  great  care  should  be 
exercised  and  time  taken  to  "  sweat  "  the  solder  well  up  into  the  lock 
of  the  seam. 

A  standing  seam  should  not  be  used  on  a  roof  of  less  than  one- 
fifth  pitch;  as,  on  a  flatter  roof,  while  it  may  be  tight  for  rain,  in 
the  winter  the  snow  and  ice  will  cause  the  water  to  back  up  under 
the  seam. 

Tin  roofing  should  always  be  painted  on  the  under  side  to  pre- 
vent rusting;  a  layer  of  good  rosin-sized  paper  directly  on  the 
sheathing  is  of  great  benefit,  as  it  absorbs  the  moisture  from  the  rooms 
below,  and  acts  as  a  cushion  to  the  tin. 

The  metal  type  of  roofing  is  the  most  expensive,  but  is  very 
durable  (where  a  good  grade  of  block  tin  or  copper  sheeting  is  used) 
and  least  troublesome  if  properly  cared  for;  e.g.,  if  a  tin  roof 
receives  a  coat  of  paint  composed  of  raw  linseed  oil  and  iron  oxide, 
once  every  two  years,  its  life  will  be  prolonged  indefinitely.  Perhaps 
the  most  objectionable  feature  present  in  a  tin  roof  is  its  capacity  for 
absorbing  heat,  which  it  retains,  often  to  the  great  discomfort  of 
dwellers  directly  underneath  such  a  roof.  Most  roofers  are  very 
expert  in  the  application  of  this  type  of  roofing,  hence  it  is  more 
important  to  obtain  a  good  quality  of  material  than  to  issue  exhaust- 
ive instructions  for  applying  it. 

FELT  (OR  COMPOSITION,  OR  BUILT-UP)  ROOFING 

Applying  Felt  Roofing.  The  third  and  most  modern  method  is 
the  Felt  or  Composition  roof.  A  felt  roof  generally  consists  of  several 
plies  of  treated  felt  (a  product  of  rag,  pulp  or  asbestos)  laid  on  a 
properly  prepared  surface  and  cemented  together  with  coal-tar 


IMPERVIOUS  ROOFING  109 

pitch  or  asphalt  and  generally  (except  the  asbestos  felt  roofing) 
covered  with  slag,  stone  screenings  or  gravel  (see  Figs.  113  and  114). 
The  felt  may  be  treated  with  asphalt,  oil  tar,  or  coal  tar,  but  the 
impregnation  must  be  thorough  in  any  case.  The  slag  or 
gravel  must  cover  the  entire  roofing  surface  so  as  to  protect 
the  bituminous  coating  from  direct  exposure,  and  to  add  weight 
to  the  membrane.  For  approximate  weights  of  various  roofings, 
see  Table  XXXVI. 

The  method  of  applying  felt  roofings  is  practically  standard; 
still,  roofers  and  builders  may  find  the  following  directions  helpful. 
These  directions*  represent  the  best  practice,  but  refer  only  to  coal- 
tar  pitch  binder  and  felt.  However,  any  good  grade  asphalt  binder 
(of  the  right  consistency  for  the  local  climate)  and  felt  might  be 
substituted,  and  equally  good  results  obtained. 

First:  One  thickness  of  sheathing  paper,  or  unsaturated  felt, 
weighing  not  less  than  5  pounds  per  100  square  feet,  is  applied,  lapping 
the  sheets  at  least  1  inch. 

Second:  Two  plies  of  saturated  felt,  weighing  14  to  16  pounds 
per  100  square  feet,  are  applied,  lapping  .each  sheet  17  inches  over 
the  preceding  one,  nailing  as  often  as  is  necessary  to  hold  it  in  place 
until  the  remaining  felt  is  laid. 

Third:  The  entire  surface  is  then  uniformly  coated  with  straight- 
run  coal-tar  pitch. 

Fourth:  Three  plies  of  treated  felt  are  laid,  lapping  each  sheet 
22  inches  over  the  preceding  one,  and  mopping  the  pitch  the  full 
22  inches  on  each  sheet,  so  that  in  no  place  shall  felt  touch  felt. 
Such  nailing  as  is  necessary  shall  be  done  so  that  all  nails  will  be 
covered  by  not  less  than  two  plies  of  felt. 

Fifth:  Over  the  entire  surface  is  spread  a  uniform  coating  of 
pitch,  into  which,  while  hot,  is  embedded  not  less  than  400  pounds 
of  gravel,  or  300  pounds  of  slag  to  each  100  square  feet  of  surface. 
The  gravel  or  slag  should  be  from  J  to  f  inch  in  size,  dry  and  free 
from  dirt. 

The  shea'ching  paper,  or  unsaturated  felt,  is  placed  on  the  bottom 
next  to  the  roof  boards,  mainly  to  keep  any  pitch  which  might 
penetrate  the  2-ply  felt  above  it  from  cementing  the  roofing  to  the 
sheathing  boards.  It  also  is  of  value  in  preventing  the  drying  out 
of  the  roof  through  open  joints  from  below.  The  saturated  felts 
should  be  nailed  not  only  to  hold  it  in  place  while  laying,  but  where 
there  is  any  chance  of  disturbance  of  the  roof  from  underneath  by 
the  wind.  The  practice  in  regard  to  nailing  varies  in  different 

*  Proceedings  of  Engineers'  Society  Western  Pennsylvania,  October,  1911. 


110  WATERPROOFING  ENGINEERING 

parts  of  the  country,  but  the  fewer  nails  the  better,  so  long  as  the 
roof  is  held  in  place. 

The  two  layers  of  saturated  felt  first  laid  are  necessary  in  order 
to  carry  and  give  full  value  to  the  amount  of  pitch  which  must  be 
handled  in  one  mopping. 

For  a  concrete  roof,  where  the  pitch  does  not  exceed  1  inch  in  1 
foot,  nailing  is  not  necessary,  and  the  practice  of  applying  the  felt 
membrane  is  similar  except  that  a  dry  sheet  is  not  necessary,  the 
concrete  being  first  coated  with  pitch  and  the  first  two  layers  mopped 
the  full  17  inches.  Special  care  should  always  be  taken  in  regard 
to  flashing  and  to  prevent  the  roofing  from  being  loosened  at  the 
edge  either  by  wind  or  fire.  Most  leaks  occur  around  flashings 
and  openings. 

After  the  original  two  layers  of  saturated  felt  are  used,  the 
additional  layers  are  merely  to  give  additional  thickness  of  wearing 
material,  and  with  a  roof  properly  laid,  the  greater  the  amount  of 
felt  and  pitch  used  the  greater  the  life  of  the  roof.  Five  plies  are 
sufficient  for  most  roofing  purposes  and  when  well  applied  make  a 
very  good  roof  covering. 

The  coating  of  gravel,  crushed  stone  or  slag  helps  to  hold  the 
coal-tar  pitch  in  place,  protects  it  from  wear  and  from  the  action  of 
the  elements;  it  also  has  considerable  fire-retarding  value.  Slag  is 
better  than  rounded  gravel  for  moderately  steep  roofs,  because  be- 
sides having  sufficient  weight  it  has  exceptional  bonding  power. 
But  if  the  mineral  coating  material  be  too  fine  its  holding  power  is 
lessened.  If  it  be  too  large  the  stones  may  cause  damage  to  the  roof 
when  it  is  walked  upon  and  are  more  apt  to  roll  off.  Crushed 
material  with  rough,  sharp  edges  has  a  much  better  holding  power 
than  rounded  gravel.  Sand  or  dirt  mixed  with  the  gravel  is  objec- 
tionable, as  it  tends  to  prevent  the  gravel  from  bedding  itself  in  the 
pitch.  Sometimes  the  sand  mixes  with  the  pitch,  the  resultant  being 
more  inert  and  liable  to  crack  than  the  clean  pitch. 

In  the  final  mopping  of  a  felt  roof  the  effect  is  to  get  the  maximum 
amount  of  coal-tar  pitch  coating  which  can  be  kept  in  place.  The 
flatter  the  roof  the  greater  the  amount  of  pitch  that  can  be  used  and 
the  better  the  pitch  and  gravel  will  stay  when  put  in  place. 

The  melting-point  of  the  pitch  should  be  varied  to  suit  climatic 
conditions.  This  variation  is  easily-  accomplished  because  it  only 
depends  upon  the  source  of  the  tar,  and  the  point  to  which  the  dis- 
tillation of  the  coal-tar  is  carried  in  the  process.  But  the  melting- 
point  of  pitch  is  not  definite  and  in  defining  it  for  a  particular  pur- 
pose and  locality  a  specification  is  advisable.  The  use  of  a  pitch 


IMPERVIOUS  ROOFING  111 

with  a  melting-point  too  high  to  allow  satisfactory  working  and 
requiring  the  addition  of  a  flux  on  the  work,  giving  what  is  known 
as  a  "  cut-back  "  pitch,  should  not  be  allowed. 

The  best  results  are  obtained  when  the  slope  of  the  roof  is  only 
enough  to  allow  it  to  thoroughly  drain.  A  method  which  gives  good 
results  on  steeper  roofs  is  the  addition  of  some  asphalt  to  the  pitch 
which  is  used  for  the  top  coating.  This  must  be  carefully  done,  as  an 
intimate  mixture  of  the  asphalt  and  coal-tar  pitch  is  not  easily 
obtained.  Coal-tar  pitch  is  often  prepared  for  use  on  moderately 
steep  slopes  by  the  addition  of  some  finely  ground  inert  material, 
but  this  is  liable  to  give  uncertain  results  unless  the  mineral  dust  is 
thoroughly  and  uniformly  mixed  throughout  the  mass.  Powdered 
slate  and  actinolite*  are  much  used  for  this  purpose.  Portland 
cement  and  plaster  of  Paris  are  also  used. 

In  place  of  felt  alone,  for  building  up  this  membrane-roofing, 
treated  jute  or  cotton  fabric  is  sometimes  alternated  between  plies. 
While  a  stronger  membrane  results  no  other  advantage  accrues  to 
the  roofing  to  counterbalance  the  increased  cost  thereof,  even  when 
the  number  of  felt  plies  is  reduced  thereby. 

Where  waterproofing  and  fireproofing  are  equally  important,  an 
asbestos  roofing  felt  is  often  used.  The  asbestos,  being  a  mineral, 
besides  being  fire-resistant,  has  the  advantage  that  it  will  not  decay. 
It  is  not  as  absorbent  of  the  preservative  though,  as  felt.  This 
type  of  roofing  is  ordinarily  applied  only  by  the  manufacturer. 
It  usually  consists  of  one  or  more  plies  of  asbestos  felt,  with  a 
strengthening  material,  such  as  jute  or  cotton  fabric,  in  the  center, 
and  cemented  together  with  asphaltic  compounds.  Here  the  reinforc- 
ing fabric  is  essential  due  to  the  extreme  weakness  of  the  asbestos 
felt.  Roofs  composed  of  this  material  usually  do  not  need  slag  or 
gravel,  thereby  reducing  the  weight  and  presenting  a  clean,  smooth 
finished  surface.  The  absence  of  slag  or  gravel  incidentally  precludes 
the  possibility  of  clogging  down-spouts  and  gutters,  which  seems 
almost  an  unavoidable  defect  of  all  felt  roofs  with  mineral 
coverings. 

Asbestos  felt  roofs  of  the  built-up  type  are  applied  over  boards 
as  follows:  First,  a  composite  membrane  composed  of  one  untreated 
asbestos  sheet  and  one  treated  sheet  (usually  combined  at  the 
factory)  is  laid  on  the  roof  boards,  lapping  and  cementing,  and 
nailing  the  sheets  every  2  inches,  with  the  untreated  side  down. 
This  is  followed  with  two  more  sheets  of  impregnated  asbestos  felt, 
placing  these  succeeding  sheets  so  as  to  always  break  joints  and 
*  A  calciUm-magnesium-iron  mineral. 


112  WATERPROOFING  ENGINEERING 

having  the  next  nailing  in  the  center  of; the  sheet  thereunder.  All 
nails  are  on  the  under  edge,  protected  by  the  asbestos  and  binder. 
Each  sheet  is  mopped  .its  full  width. 

Asbestos,  felt  roofing  over  concrete  is  laid  the  same  way  as  over 
boards,  except  that  usually  three  impregnated  sheets  are  used  as 
described.  Sometimes  the  concrete  is  first  coated  with  a  liquid 
priming  coat,  making  it  possible  for  the  hot  bitumen  to  better  stick 
to  the  concrete  surface. 

-  VARIETIES  OF  PREPARED  OR  READY  ROOFINGS 

To  reduce  cost  and  labor,  and  to  meet  some  of  the  conditions 
wherein  a  built-up  roof  is  not  satisfactory,  innumerable  substitutes 
are  made  and  sold  extensively  in  the  form  of  "  ready  "  or  "  prepared  " 
roofings.  They  are  of  special  value  for  steep  roofs  and  temporary 
structures.  Ready  roofings  consist  mainly  of  thick,  heavy,  specially 
treated  rag  or  pulp  and  wool  felt,  covered  on  one  or  both  sides  with 
rather  .tough  bitumen,  leaving  a  smooth  or  corrugated  finish  similar 
of  prepared  shingles  (see. Fig.  34,  A),  and  sometimes  also  surfaced 
with  fine  sand  or  grit  (Fig.  34,  B),  or  stone  screenings  (Fig.  34,  C). 
The  amount  of  surfacing  material. that  can  be  used  is  limited  to  the 
amount  that  can  be  successfully  rolled  on  the  felt.  If  the  particles 
are  too.  large  they  may  damage  the  felt  in  rolling.  Ready  roofings 
are  also  made. of  one,  two,  or  three  plies  of  thin  treated  felt,  bonded 
and  surface  coated  with  asphalt  or  coal-tar  pitch  in  the  factory,  and 
applied  as  individual  sheets  in  the  field.  Coal  tar,  however,  is  not 
considered  the  best  material  for  a  high-grade  ready  roofing.  These 
and  other  varieties  are  made  up  in  rolls  of  standard  widths  and 
weights,  of  one  and  two  squares,  accompanied  by  the  nails  and 
cement  necessary  to  apply  them.  The  standard  width  is  36  inches, 
and  the  standard  weights  are:  35  pounds  for  one  ply,  45  pounds 
for  two  plies,  and  55  pounds  for  three  plies.  However,  there  is  no 
uniformity  of  practice  among, the  different  manufacturers.  In  apply- 
ing these  sheets  they  are  usually  laid  in  the  direction  of  the  width  of 
the  roof,  overlapping  from  2  to  6  inches,  cemented  with  a  bitumi- 
nous solution  (usually  some  bitumen  dissolved  in  a  volatile  oil),  and 
nailed  down  with  the  nails,not  more  than  2  inches  apart.  The  best 
type  of  nails  are  made;of  'No.l?  gauge  wire,  with  a  cap  made  of  cold- 
rolled  hoop  steel  welded  bt  in  the  .factory. 

Prepared  roofings  are  'cheap,  easily  applied,  and  quite  durable, 
but  as  a  class,  somewhat  inferior  to  a  first  class  built-up  roof.  The 
weakest  points  abo.ut  ready  roofing  are  the.  narrow  laps  and  the  fact 


IMPERVIOUS  ROOFING 


113 


114  WATERPROOFING  ENGINEERING 

that  usually  a  large  part  of  the  roof  is  covered  with  but  one  layer 
of  the  material,  hence  a  single  break  will  cause  a  leak. 

There  are  a  great  many  varieties  and  qualities  of  ready  roofing, 
the  heavier  varieties,  in  general,  being  more  desirable.  There  are 
also  many  methods  for  holding  them  down  against  weather  con- 
ditions. Fig.  35  shows  ready  roofing  applied  to  a  flat  roof,  lapped, 
and  nailed  down  with  metal  cleats.  So  or  similarly  protected, 
these  roofings  are  equally  serviceable  for  flat  and  pitched  roofs. 

Applying  Ready  Roofings.  There  are  various  ways  of  applying 
prepared  roofing,  depending  on  whether  utility  or  architectural 
effects  are  most  desirable.  To  secure  the  latter  effect,  the  roofing 
felt  should  be  applied  with  the  pitch  of  the  roof,  the  joints  and  roofing 
nails  being  covered  with  a  molded  batten  of  wood,  about  f  inch  by  1 J 
inches.  The  under  side  of  this  batten  should  be  rabbeted  to  a  depth 
of  |  inch  to  make  room  for  the  heads  of  the  roofing  nails.  The  rabbet 
should  be  filled  with  a  plastic  cement,  such  as  accompanies  the  roof- 
ing, and  the  latter  then  securely  nailed.  Roofs  so  prepared  have  the 
appearance  of  a  standing-seam  tin  roof.  The  most  common  method 
of  applying  ready  roofings,  however,  is  as  follows: 

A  good  foundation  for  the  roofing  is  very  important.  Hence  the 
practice  advised  for  applying  sheathing  boards  in  connection  with 
shingle  roofs  is  directly  applicable  here.  Also  in  the  case  of  cracks 
or  knot  holes,  in  the  boards  it  is  good  practice  to  tack  pieces  of 
tin  over  them.  If  the  weather  is  warm,  the  ready  roofing  should  be 
unrolled  and  allowed  to  lie  exposed  to  the  sun  and  air  to  thoroughly 
flatten  out,  and  stretched  before  being  nailed  down,  otherwise  it 
may  wrinkle  or  buckle.  If  the  weather  is  cold,  the  roofing  should  be 
kept  in  a  warm  room  just  before  it  is  unrolled  and  used,  taking  special 
care  to  stretch  it  out  thoroughly  and  nailing  it  in  place  while  still 
warm.  Sheets  should  not  be  cut  when  spread  on  top  of  those 
already  laid,  nor  should  the  roofing  be  torn,  but  always  cut  with  a 
sharp  knife  to  insure  straight  edges.  For  very  steep  roofs  it  is  often 
better  to  cut  the  desired  lengths  on  the  floor.  It  is  very  important 
to  plan  the  work  in  advance  as  far  as  possible,  particularly  at  flash- 
ings, around  vertical  walls,  chimneys  or  any  other  projections  from 
the  roof  and  at  laps  or  joints. 

The  roofing  material  should  always  be  laid  so  as  to  have  the 
seams  or  laps  run  parallel  with  the  sheathing  boards,  as  this  arrange- 
ment will  insure  a  uniform  and  even  nailing  surface  for  securing  it. 
Great  care  is  required  to  see  that  the  roofing  laps  over  solid  sheathing 
boards,  and  not  over  a  joint  or  crack.  If  a  lap,  on  account  of  the 
position  of  a  previous  sheet,  should  occur  so  as  to  bring  the  nailing 


IMPERVIOUS  ROOFING 


115 


116  h  WATERPROOFING  ENGINEERING 

•r    ,*        '  t  •          •     .-..--..  ~    -»>..-  .. 

points  directly  over  a  joint  or  a  crack  in  the  sheathing  boards, 
the  next  sheet  should  be  shifted  an  inch  or  two  so  as  to  avoid 
the  crack. 

Upon  a  flat  roof  the  sheets  are  laid  with  the  slope  of  the  roof 
when  the  sheathing  boards  run  that  way.  Beginning  at  the  left, 
the  first  sheet  is  unrolled  and  placed  so  as  to  permit  about  3  inches 
to  extend  up  against  the  fire  wall,  or  in  the  event  that  the  roofing  is 
turned  over  sheathing  boards  at  the  side,  1  or  2  inches  should  be 
allowed  for  this  purpose,  and  from  1J  to  2  inches  at  the  eaves  or 
end'^of  the  sheet.  This  sheet  must  be  carefully  adjusted  and  flattened 
into!  position,  folding  the  sheet  carefully  where  it  projects  against 
the  ifire  wall  so  as  to  make  a  good  corner  without  breaking  the  felt. 
It  is  temporarily  secured  in  place  by  driving  a  few  nails  along  its 
edg£  and  end;  then  the  next  sheet  is  unrolled,  allowing  it  to  overlap 
at  (east  2  inches,  being  careful  to  obtain  a  uniform  lap  along  the 
entire  seam.  After  this  second  sheet  is  carefully  adjusted  and 
flattened  out,  it  should  be  nailed  directly  over  the  2-inch  lap,  placing 
the  nails  within  J  inch  of  its  edge.  This  is  repeated  until  the  entire 
roof  is  covered. 

Making  watertight  flashings  against  fire  walls,  is  equally  as 
important  as  making  watertight  joints  between  plies  and  laps  in 
the! various  roofing  materials.  This  is  discussed  in  the  following 
article. 

i 

ROOF  FLASHINGS 

'An  important  part  of  the  construction  of  roofs  and  roof  parapet 
walls  on  large  brick  or  concrete  buildings  is  the  flashing.  Flashing 
may  be  defined  as  a  piece  of  metal  or  waterproof  material  used  to 
keep  water  from  penetrating  the  joints  principally  between  a  fire 
wall  or  projection  through  the  roof  of  a  building  or  other  structure. 
Its 'efficient  location  and  application  as  well  as  the  selection  of  the 
best  material  are  matters  that  require  careful  study.  For  general 
work  most  roofers  can  supply  and  apply  flashings  meeting  all  re- 
quirements. 

The  vital  part  of  a  brick  parapet  wall  is  the  inner  side,  which 
heretofore  was  made  up  of  common  brick  laid  up  in  ordinary  lime 
mortar.  As  a  result,  and  owing  to  the  freezing  of  the  brick  above 
the  roof  flashing — due  to  saturation  from  snow  or  rain — many  brick 
parapet  walls,  after  a  few  years  became  a  crumbling  mass.  In 
consequence  the  flashing  became  loosened  and  water  percolated 
through  the  joints  to  the  detriment  of  the  interior,  To  avoid  the 


IMPERVIOUS   ROOFING  117 

above  condition  it  is  now  the  practice  to  build  the  inner  side  of  the 
brick  parapets  of  hard  burned  vitrified  brick  laid  up.  in  cement 
mortar  and  covering  the  top  with  a  waterproof  Doping;-,  ;  In  addi- 
tion to  this  the  roofing  material  is  sometimes  carried": up  to  the 
under  side  of  the  coping.  But  a  common  procedure  .Is. '  to  take 
one  or  more  strips  of  felt  or  ready  roofing  about  12  inches  wide, 
folded  in  the  center  and  fitted  into  angles  at  fire  walls,  chimneys, 
etc.,  so  that  6  inches  project  up  these  surfaces  and  6  inches  lap  over 
the  roofing.  These  strips  are  fastened  (if  more  than  one  is  used 
as  on  composition  roofs)  with  a  row  of  nails  at  the  upper  edge  of  the 
upper  strip  by  driving  them  into  the  mortar  joints  between  the 
bricks,  and  securing  the  lower  edges  (if  ready  roofing  is  being  applied) 
with  a  row  of  nails  applied  similar  to  an  ordinary  lap,  or  by  mopping 
with  pitch  or  asphalt  (if  composition  roofing  is  applied)  and  com- 
pletely coating  the  surface  of  the  flashing  strip  as  is  ordinarily  done 
on  the  roofing  proper.  All  flashings  on  brick  walls,  etc.,  should  be 
counter  flashed  with  metal  so  as  to  prevent  water  from  eventually 
working  in  behind  them.  These  counter  flashings  must  be  thoroughly 
secured  in  a  mortar  joint  above  the  roof  flashings  and  turned  down 
over  the  seam  for  at  least  4  inches.  For  buildings  subjected  to 
gases  and  fumes,  saturated  felt  properly  coated  with  good  asphalt 
or  pitch  preparations  will  give  good  results.  For  buildings  located 
outside  of  industrial  centers,  non-corrosive  metal  flashings  give  very 
good  results.  A  very  efficient  means  of  fastening  both  the  flashing 
and  counter  flashing  is  shown  in  detail  (applicable  both  for  com- 
position and  ready  roofing  at  parapets)  in  Fig.  36.  This  detail, 
recommended  as  good  practice  by  the  American  Railway  Engineering 
Association,*  makes  use  of  a  2-  by  4-inch  timber  with  one  edge 
beveled,  laid  continuous  in  the  parapet  at  the  proper  height  in  place 
of  a  stretcher  course  of  brick.  This  serves  as  a  nailing  strip  for  a 
light  wooden  strip  holding  the  flashing  and  counter  flashing  in  place. 
After  placing  the  flashing  the  slot  is  completely  sealed  up  with  cement 
grout  or  roofing  cement. 

For  the  proper  flashing  of  concrete  parapet  walls  the  detail  shown 
in  Fig.  36  can  be  recommended.  *  A  2-  by  4-inch  piece  of  lumber  is 
ripped  on  the  diagonal  as  shown  and  then  placed  in  the  forms  at  the 
desired  height,  the  upper  strip  being  securely  nailed  thereto,  so  as  to 
insure  its  removal  when  forms  are  taken  down,  while  the  lower  piece 
is  just  tacked  to  forms  (from  outside)  with  wires  or  nails  driven  into 
it  as  shown  to  anchor  it  to  the  concrete.  The  flashing  and  counter 
flashing  are  then  placed  in  the  same  manner  as  for  brick  walls. 
*  Concrete.  Vol.  9,  No.  6,  December,  1916,  p.  197. 


WATERPROOFING  ENGINEERING 


An  ingenious  and  inexpensive  flashing  is  shown  in  Fig.  37.  The 
metal  lock  referred  to  in  the  diagram  is  of  galvanized  sheet  iron, 
and  acts  as  the  backbone  for  the  flashing,  which  may  be  made  of 
ordinary  felt  or  strips  of  prepared-roofing  felt,  these  often  being 
substituted  for  the  more  expensive  all-metal  flashings. 


2 'x  4  (Continuous1) 

Seal  of  Cement  Grout 
or  Roofing  Cement 


BRICK  PARAPET 
A 


CONCRETE  PARAPET 
B 


FIG.  36.— Flashing  Details. 


ROOF  CUTTERS 

The  function  of  impervious  roofing  is  to  shed  the  rainwater  so 
that  none  finds  entrance  into  the  building.  On  small  and  unim- 
portant structures,  rainwater  is  allowed  to  drip  off  the  eaves,  often 
discoloring  the  walls.  On  most  structures,  however,  both  large  and 
small,  provision  is  made  for  taking  care  of  the  drip  by  providing 
gutters  directly  under  the  eaves,  or  other  roof  plane,  and  in  the 
valleys  of  the  roof.  The  most  modern  practice  is  to  slope  the  roofs 
of  buildings  so  as  to  provide  drainage  in  the  direction  of  the  center 
of  the  structure,  where  the  gutters  and  conductors  are  arranged  for 
easy  access.  This  arrangement  avoids  marring  the  architectural 
effect  of  the  facade.  Fig.  38  shows  typical  arrangements  of  metal 
gutters  and  conductors,  for  mill  and  factory  buildings. 


IMPERVIOUS  ROOFING 


119 


Portion  of  lock 
before  hammered 


Metal  lock  is  hammered  to 
ready-roofing  flashing-strip* 

gripping  same  by  means  of 
clinch  holes  in  the  lock 


Joints  are  filled  with 
cement  mortar  or 
flexible  cement. 


Mopped 
underneath 
with  pitch 
or  asphalt. 


FIG.  37.— Showing  Method  of  Using  Felt  in  Place  of  Metal  Flashings.     (Metal 
Lock  Illustrated  is  Patented.) 


Adjustable 
ffanger 
every 


FIG.  38.— Eave  and  Valley  Gutters  of  Galvanized  Iron  or  Steel.     (American 
Bridge  Co.'s  Standards.) 


120  WATERPROOFING  ENGINEERING 

Gutters  should  be  sloped  not  less  than  1  inch  in  15  feet,  and 
if  made  of  sheet  iron,  or  steel,  should  preferably  be  galvanized  than 
tinned  because  the  latter  variety  corrodes  more  easily  around  an 
abrasion  or  other  slight  damage.  The  gutters  and  leaders,  or  con- 
ductors, made  of  these  metals  should  be  of  No.  22  to  20  gauge 
(18  to  22  ounces  per  square  foot).  On  the  better  class  of  structures, 
gutters  and  conductors  are  usually  made  of  copper,  in  which  case 
the  metal  used  varies  in  weight,  from  14  to  20  ounces  per  square  foot. 
Hanging  gutters  are  frequently  made  of  considerable  length;  there- 
fore they  should  be  strongly  built,  as  otherwise  they  are  liable  to 
deflect  from  a  uniform  grade.  Simple  and  inexpensive  gutters  are 
often  made  by  fastening  a  strip  of  wood,  of  appropriate  size,  close 
to  the  end  of  the  eave  of  the  roof  and  sloping  towards  the  conductor. 
This  strip  runs  along  the  entire  length  of  the  eave,  and  is  covered 
by  the  material  used  for  the  roofing,  or  by  sheet  metal.  This 
practice,  however,  is  mainly  resorted  to  on  low  buildings,  such  as 
mill  buildings  and  small-town  railroad  stations. 

FUNCTIONAL  ROOFINGS 

Definition,  Use  and  Varieties  cf  Functional  Roofings.  Functional 
roofings  consist  of  such  materials  as  both  waterproof  and  roof  the 
uppermost  part  of  a  structure;  that  is,  they  are  compositive  and 
include  all  those  not  covered  by  the  previous  types  of  roofings. 
Most  of  the  functional  roofings  are  of  recent  origin  and  have  a 
limited  use  because  they  are  usually  adapted  to  special  types  or 
temporary  structures.  They  are  for  the  most  part  though,  efficient 
and  often  inexpensive.  The  following  are  examples  of  functional 
roofings: 

Corrugated  or  crimped  galvanized  sheet  iron  (see  Fig.  39)  and 
asbestos-covered  corrugated  sheet  iron  (see  Fig.  40).  These  are 
often  used  for  the  roofs  of  freight  cars  and  small  mill  buildings; 
also  metal  shingles,  which  have  a  limited  use  on  railroad  structures. 
In  general,  however,  steel  or  impure  iron  materials  are  avoided, 
especially  on  important  structures,  even  though  these  materials  are 
protected,  because  of  the  necessity  of  frequent  repair  or  renewals. 
The  structural-composite  roofing  shown  in  Fig.  41  is  serviceable 
for  train  sheds,  depots,  and  large  mill  buildings.  Heavy  cotton 
canvas,  sometimes  treated  with  a  preservative,  but  always  painted, 
is  extensively  used  as  roofing  for  freight  and  passenger  railroad 
cars  and  on  decks  of  ferry  boats.  Glass  roofings,  for  which  there 
are  many  methods  of  making  watertight  joints  (two  of  which  are 


IMPERVIOUS  ROOFING 


121 


11        „         "        „         " 


11         ,.        "         ,.        "         „        " 


FIG.  39. — Corrugated  Galvanized-iron  Roofing,  Showing  Method  of  Lapping 

and  Flashing. 


FIG.  40. — Asbestos-covered  Corrugated  Roofing. 


122 


WATERPROOFING  ENGINEERING 


FIG.  41. — Structural-composite  Roofing. 


[ Purlin  Clip 


Cushion 

"°^          h^ 

\  \  /Condensation 

i)\ /        Gutter 


-Insulation  and 
Rust  Proofing 


Purlin  Clip | 


FIG.  42.— Two  Types  of  Watertight  Joints  in  Puttyless  Glass  Roofing.  (Patented.) 


IMPERVIOUS  ROOFING 


123 


shown  in  Fig.  42)  are  well-adapted  for  depots  and  general  skylights 
of  -buildings;  also  for  roofs  of  buildings  used  in  the  production  of 
motion  pictures.  Roofs  of  many  factory  buildings  and  all  concrete 
buildings  are  made  either  of  reinforced  concrete  or,  to  insure  better 
watertightness,  have  an  integral  waterproofing  compound  added  to 
the  concrete. 

The  method  of  applying  functional  roofings  depends  on  the 
material  and  also  somewhat  on  the  structure.  Sheet  and  corrugated 
galvanized  iron  are  usually  nailed  down  to  the  purlins  and  lapped 
both  lengthwise  and  crosswise  as  shown  in  Fig.  43,  A.  Sometimes 


FIG.  43. 

A.  Methods  of  Nailing  Down  Corrugated  Sheet  Iron  on  Roofs  and  Sidings. 

B.  Methods  of  Applying  Sheet  or  Corrugated  Roofing  to  Roof  Framework. 

small  iron  cleats  are  riveted  to  the  sheets  which  hook  on  to  angle 
irons  screwed  on  to  the  purlins  or  roof  frame  work.  Fig.  43,  B, 
shows  several  methods  in  common  use.  The  former  method  pro- 
duces a  more  durable  and  watertight  roof.  . 

The  slab  type  of  functional  roofing  is  usually  made  so  as  to  lap 
over  each  other  and  fit  into  prepared  grooves.  The  joints  are  usually 
made  watertight  with  an  adhesive,  elastic  compound. 

A  roof  built  of  concrete  blocks  or  blocks  of  any  other  material 
will  not  of  itself  be  watertight  because  of  the  many  joints;  such 
roofs  must  first  be  waterproofed  usually  with  a  membranous  roofing 
material,  hence  these  materials  cannot  be  classed  as  functional 
roofings. 


CHAPTER  IV 
WATERPROOFING  EXPANSION   JOINTS  IN   MASONRY 

Function  and  Properties  of  Expansion  Joints.  Expansion  joints 
constitute  one  of  the  basic  causes  contributing  to  the  difficulty  of 
making  masonry  structures  watertight.  When  masonry  is  to  be 
waterproofed  its  expansion  joints  must  be  so  made  that  water  cannot 
pass  through  them.  This  is  usually  accomplished  either  by  some 
form  of  tongue  and  groove,  by  a  bent  cutoff  plate,  by  gaskets,  and 
so  forth,  in  endless  variety.  Designers  usually  include  some  form 
of  bitumen  or  other  sticky,  plastic  material  as  a  joint  filler. 

To  devise  a  joint  that  will  remain  tight  under  all  conditions  of 
weather  and  stress  is  exceedingly  difficult.  Most  failures  of  water- 
proofing are  due  to  the  lack  of  joints,  to  joints  not  placed  where  the 
tensile  stress  is  large,  to  narrow  joints,  or  to  joints  which  do  not 
remain  watertight.  In  a  great  many  cases  if  an  adequate  number  of 
good  watertight  joints  were  provided  no  other  waterproofing  would 
be  required.  Concrete  and  other  masonry  can  nearly  always  be 
made  as  impervious  as  necessary  between  cracks,  and  therefore  the 
waterproofing  of  a  structure  is  often  a  question  of  waterproofing 
its  joints.  Hence,  we  shall  investigate,  (1)  the  methods  used  for 
the  proper  provision  for  expansion  and  contraction  in  concrete  or 
other  masonry;  and  (2)  the  methods  used  for  proper  waterproofing 
of  the  joints. 

Expansion  joints  are  used  in  structures  to  allow  the  masonry  to 
expand  and  contract  freely  with  changing  temperature,  and  to  per- 
mit other  necessary,  small,  internal  movements  and  readjustments. 
Expansion  joints  are,  in  fact,  simply  cracks  built  into  the  masonry 
to  anticipate  or  take  the  place  of  the  internal  cracks  and  breaks. 
A  sufficient  number  of  these  joints  must  be  provided  to  avoid  dis- 
figuring the  masonry  with  unsightly  cracks  (see  Fig.  124).  The 
following  instance  demonstrates  the  commonest  way  that  cracks 
occur  in  masonry.  Structural  materials  have  a  varying  coefficient 
of  expansion*  (see  Table  XXX). 

*  The  coefficient  of  expansion  for.  any  material  is  the  factor  which  expresses 
the  change  per  unit  of  length  for  each  degree  of  temperature. 

124 


WATERPROOFING  EXPANSION  JOINTS  IN   MASONRY      125 

The  coefficient  of  expansion  for  concrete  is  variously  assumed 
as  .0000055  or  .0000065  per  deg.  Fahr.  (about  |  inch  in  100  feet 
for  each  15  deg.  Fahr.).  These  coefficients  vary  somewhat  with 
different  proportions  and  kinds  of  aggregate  in  the  concrete.  Assum- 
ing for  concrete  a  modulus  of  elasticity  of  2,000,000  pounds  per 
square  inch  and  an  ultimate  tensile  strength  of  200  pounds  per  square 
inch,  a  distortion,  in  tension,  of  0.0001  inch  will  fracture  it.*  Fifteen 
degrees  Fahr.  drop  in  temperature  produces  this  change  in  length 
and  is  thus  just  sufficient  to  break  restrained  concrete. 

Monolithic  Construction  Obviates  Expansion  Joints.  To  avoid 
the  use  of  expansion  joints,  small  structures  are  often  built  as  mono- 
liths for  which  the  waterproofing  is  fairly  simple.  Larger  structures 
can  be  built  monolithic  by  imbedding  sufficient  steel  in  the  concrete 
so  that  the  concrete  is  not  stressed  beyond  its  breaking  strength. 

The  elimination  of  joints  by  this  method  may  be  carried  a  step 
further.  Reinforcing  metal  can  be  placed  the  whole  length  of  a 
structure  of  any  size  or  of  a  structure  whose  ends  are  restrained. 
But  in  this  case  the  function  of  the  steel  is  quite  different  from 
ordinary  reinforcing  steel.  Fifteen  degrees  drop  in  temperature  will 
break  the  concrete  as  if  the  steel  was  not  present.  But  the  intro- 
duction of  the  steel  merely  causes  the  cracks  to  be  smaller  and 
closer  together.  Steel  has  about  the  same  coefficient  of  expansion 
as  concrete.  But  the  ratio  of  ultimate  tensile  strength  to  modulus 
of  elasticity  is  so  much  greater  with  steel  than  with  concrete  that, 
while  concrete  is  broken  by  a  15  deg.  Fahr.  drop  in  temperature, 
a  drop  of  100  degrees  only  stresses  steel  to  its  safe  working  stress, 
a  drop  of  175  degrees  to  its  yield  point,  and  no  temperature  change 
whatever  is  able  to  break  it.  A  moderate  amount  of  steel  makes 
the  cracks  so  small  and  close  together  that  they  are  unnoticeable. 
The  actual  quantity  of  steel,  which  can  be  readily  computed,  varies 
between  .1  per  cent  and  .3  per  cent  of  the  cross-sectional  area 
of  the  concrete  depending  on  climate  and  local  conditions,  as, 
for  instance,  whether  the  structure  is  above  or  below  ground. 
None  the  less  it  must  be  borne  in  mind  that  the  concrete 
is  fractured  and  that  therefore  water  will  find  its  way  through, 
particularly  if  under  a  head.  The  total  cross-section  of  the  cracks 
will  be  about  the  same  in  both  cases,  but  the  capillary  and  fluid 
friction  through  the  mass  will  considerably  reduce  the  permeability 
of  the  concrete,  and  eventually  these  minute  cracks  may  be  closed  up 
with  silt,  thus  making  the  structure  completely  watertight. 

*  Modulus  of  elasticity  equals  stress  divided  by  deformation;  using  these 
values  the  deformation  is  0.0001. 


126  WATERPROOFING  ENGINEERING 

Design  and  Spacing  of  Expansion  Joints.  The  width  of  a  joint 
controls  the  longitudinal  movement  of  each  section,  and,  hence, 
controls  the  movement  of  the  entire  structure.  Therefore  expansion 
joints  should  be  large  enough  to  accommodate  any  movement  that 
may  occur  and  spaced  sufficiently  close  together  to  eliminate  all  other 
cracks  or  joints.  In  other  words,  the  joints  must  be  so  spaced  that 
under  all  conditions  of  temperature  change,  loading,  vibration,  or 
foundation  settlement,  the  masonry  between  the  joints  will  be  a 
single  monolith.  The  proper  location  and  design  of  these  joints 
require  forethought,  experience  and  good  judgment. 

To  design  a  joint,  the  change  in  length  is  computed  for  the  tem- 
perature variation  of  the  particular  climate.  This  is  increased  as 
needed  to  allow  for  other  movements,  plus  a  small  amount  as  a  fac- 
tor of  safety.  The  spacing  of  the  joints  is  determined  by  computing 
the  frictional  resistance  to  movement  between  the  masonry  surfaces. 
The  joints  must  be  so  close  together  that  the  stress  resulting  from  this 
friction  is  within  the  safe  tensile  strength  of  the  masonry.  Stresses 
due  to  other  causes  must  of  course  be  computed  and  combined  with 
the  friction  stress. 

Joints  may  be  located  at  intervals  of  from  25  to  50  feet,  although 
under  favorable  conditions  and  sufficient  reinforcement,  larger 
sections  may  be  used.  But  the  larger  the  section  between  joints, 
the  wider  should  the  joint  be  made.  For  restrained  structures  and 
large  gravity  retaining  walls,  the  maximum  distance  that  joints 
should  be  spaced  is  50  feet.  Concrete  walls  which  are  less  than  3  or 
4  feet  in  thickness,  and  subject  to  about  60  deg.  Fahr.  seasonal 
change  of  temperature,  should  have  joints  spaced  about  30  feet  apart. 

Joints  in  Brick  Masonry.  Expansion  joints  in  brick  masonry 
are  rarely  employed,  but  the  joints  between  the  bricks  require  care- 
ful attention  where  impervious  walls  are  necessary,  as  for  instance, 
in  residences. 

The  mortar  in  the  joints  of  brick  masonry  is  usually  deficient  in 
density  and  hence  is  quite  absorbent  and  more  or  less  permeable. 
Often  for  the  sake  of  enhancing  the  appearance  of  a  residence  the 
mortar  is  raked  out  of  the  joints  for  a  depth  varying  between  |  and  1 
inch  and  left  so.  This  is  poor  practice  because  very  little  mortar 
may  remain  near  the  front  face  of  the  brick  to  prevent  the  percolation 
of  water  especially  when  aided  by  a  driving  rain.  This  often  happens, 
resulting  in  damp  and  wet  interiors.  Where  it  is  proposed  to  use 
this  type  of  joint  in  the  masonry,  then,  to  make  these  joints  imper- 
vious, half  the  raked-out  space  should  be  filled  with  a  pointing 
mortar.  The  pointing  material  may  be  either  neat  cement  or  mortar 


WATERPROOFING  EXPANSION  JOINTS   IN   MASONRY      127 


composed  of  Portland  cement  and  sand  in  equal  proportions,  mixed 
with  enough  water  to  form  a  stiff  paste.  This  paste  should  be 
tamped  in  with  a  metal  calking  tool  and  the  joint  facings  can  then 
be  finished  according  to  one  of  the  pointings  shown  in  Fig.  44. 

Where  this  practice  is  not  resorted  to,  i.e.,  where  neither  raking 
nor  special  joint  mortar  are  employed,  and  where  dry  and  damp- 
proof  interiors  are  desired  (assuming  that  the  best  grade  of  bricks 
were  used)  then  the  mortar  joint' proper,  made»as  the  work  progressed, 
should  also  be  pointed  as  illustrated. 

The  Slip-tongue  and  Plane-of-weak-bond  Joints.  The  types  of 
expansion  joints  used  in  practice  are  almost  as  varied  as  the  types  of 
masonry  structures  built  nowadays.  The  simplest  expansion  joint 
for  concrete  dams,  walls,  etc.,  is  a  plane  of  weak  bond  in  the  structure, 


FLUSH  JOINT  STRUCK  JOINT        WEATHER  JOINT 

FIG.  44. — Types  of  Mortar  Joints  Used  for  Appearance  and  Utility. 

made  by  building  one  section  first  and  coating  it  with  bitumen  or 
other  compound,  or  nailing  to  it  one  or  more  plies  of  treated  felt, 
sometimes  bonded  with  bitumen,  against  which  the  concrete  of  the 
second  section  is  poured. 

That  it  is  necessary  to  create  a  plane  of  weak  bond  in  the  structure, 
by  interposing  some  form  of  coating  or  sheeting  between  the  joints 
of  all  sections,  is  evident  from  the  fact  that  the  separation  at  the 
joints  is  not  otherwise  uniformly  perfect.  When  joints  are  formed 
without  interposing  any  sheetings  or  other  separating  material, 
then  by  pouring  one  section  after  the  adjoining  section  has  set,  no 
adhesion  of  any  large  amount  would  be  expected  under  these  con- 
ditions; yet  it  often  happens  that  there  is  a  strong  enough  bond  to 
break  through  solid  concrete  alongside  the  joint.  This  is  evidenced 
by  the  many  meandering  cracks  (other  than  shrinkage  cracks)  often 
seen  close  to  and  paralleling  the  V-groove  formed  in  the  face  of 
concrete  walls  at  joints, 


128 


WATERPROOFING  ENGINEERING 


Another  phase  of  the  joint  problem  worth  noting  is  the  protection 
of  horizontal  joints.  In  the  construction  of  concrete  walls,  abut- 
ments, etc.,  almost  sole  attention  is  given  to  vertical  expansion 
joints  and  their  protection  against  the  seepage  of  water  through 
them.  Little  if  any  real  attention  is  paid  to  horizontal  joints,  and 
yet  it  is  these  joints  that  are  mostly  responsible  for  discoloration 
(see  Fig.  2)  and  equally  responsible  for  leakage  in  these  and  other 
structures.  Whether  the  horizontal  joint  be  a  days- work  joint  or  a 
construction  joint,  its  existence  is  a  source  of  danger  to  the  unity 
of  the  structure  from  the  waterproofing  point  of  view,  and  should  be 
cared  for  as  effectively  as  vertical  joints.  Fig.  45  shows  an  effective 

Lap  Joint- Strips 
joined  by  heatin 

faces 

Expansion  Joint, 
non-flowing 

filler 
B 


SECTION  A-A 


Construction 
Joints 


,,. 

A 

':?'•- 

1 

^                                         Asphalt  Strip  Baffle^ 
^Construction  Joints             *  x  M  x  8' 

1 

^^•Viscous  Bituminous  Compound 

j: 

r  -r.-;^:^-  :^-^:t--  :-:•?*:  •:*.-:• 

SECTION  B-B   (COMPLETED) 

WALL 


""Joint  Coated  with  Paraffine 


FIG.  45. — Location  of  Horizontal  Baffle  Joints  in  Walls  and  Tanks. 


method  of  waterproofing  horizontal  joints.  Its  efficiency  is  some- 
times doubtful  because  the  slip  tongue,  which  is  generally  made  of 
sheet  iron,  and  though  sometimes  painted  with  a  preserving  com- 
pound, too  often  corrodes  and  vitiates  its  function.  What  should  be 
used  as  a  slip  tongue  to  avoid  such  defects  is  a  non-corrosive  material 
and  such  may  be  made  of  tough  elastic  asphalt  strips  similar  to  the 
precast  expansion  joint  fillers  used  in  concrete  road  construction. 
Fig.  48  shows  such  a  scheme  of  protecting  horizontal  joints  in  which 
the  barrier  is  placed  on  the  finished  concrete  in  the  form  of  a  strip, 
before  the  new  concrete  is  deposited. 

Illustrations  of  Expansion  Joints.     One  requisite  for  all  forms 
of  expansion  joints  is  that  they  be  so  constructed  as  to  retain  the 


WATERPROOFING  EXPANSION  JOINTS  IN   MASONRY      129 


joint  filler  (which  alone  waterproofs  the  joints)  as  long  as  the  struc- 
ture lasts.  A  second  requisite  is  that  the  joint  filler  itself  retain  its 
properties,  and  last  equally  as  long,  or  allow  of  replacement  at 
definite  intervals.  The  first  requisite  will  be  well  provided  for  by 
adhering  to  the  basic  type  of  joints  shown  in  Fig.  46,  modified,  of 
course,  to  conform  to  any  special  requirement.  The  second  requisite 
will  be  satisfied  by  any  material  which  does  not  lose  its  "  body  " 
or  substantial  character,  adhesiveness  and  elasticity,  at  least  not 
rapidly,  and  is  not  affected  by  water.  Such  compounds  are  dis- 
cussed further  on  in  this  chapter. 

Front  of  Walk 


Slab 


^     M 


:':^x.l#:V.v-:i-.v 

•rr~'.  .  '*•-'*  '  *V-  '  ' 


/.:-£V::v.:.:d.:..ij.;.: 


VERTICAL  EXPANSION  JOINTS 


x-Joint  Filler 


Joint  Filler 


1  Stiiieifc?d:^ah?i; 


D  E 

HORIZONTAL  EXPANSION  JOINTS 
FIG.  46.— Basic  Types  of  Waterproofed  Expansion  Joints. 

Fig.  47  (A,  B,  C  and  D)  is  taken  from  a  report  by  the  Committee 
on  Buildings  and  Structures  of  the  American  Electrical  Railway 
Engineers  Association.  These  joints  have  several  interesting 
features  which  are  evident  and  self-explanatory. 

Fig.  48  illustrates  a  method  of  waterproofing  horizontal  and 
vertical  joints  in  concrete  walls;  the  former  by  means  of  gaskets  or 
strips  of  fabric  thickly  coated  with  a  bituminous  material ;  the  latter 
by  means  of  rolls  of  the  same  material  fitted  in  a  prepared  groove  of 
one  section  and  surrounded  by  the  concrete  as  poured  for  the  next 


130 


WATERPROOFING  ENGINEERING 


J  " 

'"4 

4. 

<-12" 

i 

•    !i 

^ 



ELEVATION 


A,  EXPANSION  JOINT  FOR  RETAINING  WALL" 


A 
f 

"•  Separation  made! 
by  insertion  of 
waterproofing 
material 


£.  Stone  laid 
.dry  packed 
/against  wall1 
xfor  3'0'at  each 
expansion 
joint  and 
weep  hole. 


J.  EXPANSION   JOINT  FOR 
ARCHED  ROOF  OR  SIDE  WALL 


•Top  of  Platform 


G.  EXPANSION  JOINT  FOR  ARCH 
OR  RETAINING  WALL 


D.  EXPANSION   JOINT  FOR 
PLATFORM 


FIG.  47. — Typical  Forms  of  Waterproofed  Expansion  Joints  Used  for  Various 

Structures. 


WATERPROOFING  EXPANSION  JOINTS  IN   MASONRY      131 


section,  with  the  rest  of  the  joint  between  sections  filled  with  several 
plies  of  treated  felt.  It  is  possible  to  make  very  efficient  expansion 
joints  in  this  manner,  provided  the  compound  used  for  treating  the 
fabric,  of  which  the  gaskets  and  rolls  are  made,  remains  tacky  and 


Back  of  Wall 


\ 


&ET 

-Flap 

id 

- 

^ 

yl 

Horizontal  Joint/ 
Filler.  2  Layers 

^  v- 

I 
^Vertical  Joint  Filler, 
Tight  Roll,  ±  3  Dia. 

«r 

h 

—  3  Ply  Treated  Felt 

SECTION  A-A 


FIG.  48. — Horizontal  Waterproof  Baffle,  and  Vertical  Expansion  Joint  and  Joint 
Filler  Used  on  Concrete  Retaining  Wall  of  the  Brighton  Beach  Line,  B.R.T. 
Railroad  System,  Brooklyn,  New  York. 


adheres  to  the  concrete  when  set,  and  elastic,  so  that  it  "  gives  " 
when  contraction  and  expansion  take  place. 

Fig.  49  shows  a  horizontal  joint  for  a  concrete  floor.  This  joint 
is  waterproofed  by  means  of  a  copper  V-joint  anchored  and  filled 
with  a  joint  roll,  consisting  of  treated  fabric  wound  tightly  on  itself 
and  covered  with  some  tenacious  and  elastic  compound,  which  when 


132 


WATERPROOFING  ENGINEERING 


the  joint  contracts,  forms  a  bulb  upward,  and  on  expansion  forms  a 
groove.  But  this  operation  is  only  possible  when  the  joint  filler 
adheres  tenaciously  to  the  sides  of  the  joint. 


iiSHiHl 


FIG.  49. — Type  of  Waterproofed  Expansion  Joint  Used  on  Public  Service  Railway 
Terminal,  Newark,  N.  J. 


Fig.  50  is  a  form  of  expansion  joint  advocated  for  solid  bridge 
floors,  and  patented  by  Mr.  A.  H.  Rhett,  Engineer.  Fig.  51  (A  and  B) 
is  from  the  Waterproofing  Specifications  of  the  Chicago,  Milwaukee 
and  St.  Paul  Railway,  and  shows  their  method  of  waterproofing 


•j.-jy.;-:c--»:ii:»-'^:-.:p.-:w--  j     [\-~.-m\o  •>  o  *v:-X2&-B-ff.W.&Wt^. 


FIG.  50. — Waterproofed  Expansion  Joint  for  Solid  Floor  Bridge.     (Patented.) 


bridge  floor  expansion  joints.  This  method  consists  in  applying 
two  continuous  strips  of  treated  felt,  36  inches  wide,  over  the  expan- 
sion joints,  being  careful  to  see  that  no  bitumen  gets  between  or 
under  the  two  strips  of  treated  felt.  Then  the  top  strip  is  mopped 
with  hot  bitumen  and  the  waterproofing  proper  carried  over  the  top 
of  the  felt  as  if  no  joint  existed. 


WATERPROOFING  EXPANSION  JOINTS  IN   MASONRY      133 

The  joint  shown  in  Fig.  52,  A,  is  a  vertical  square  or  rectangular 
recess  filled  with  plastic  clay.  The  clay  must  be  of  the  best  quality, 
placed  while  wet  and  rammed  absolutely  solid  into  place,  otherwise 
it  will  not  cohere  into  a  unit  mass.  Fig.  52,  B,  shows  tne  rectangular 
and  triangular  tongue-and-groove  types  of  joints  commonly  used 
for  small  masonry  bridges  and  abutments,  parapet  walls  and  retain- 


2  Layers  of  Tar  Paper 


SECTION  OF  EXPANSION-JOINT 
ON   LEVEL   SURFACE 
A 


Expanded  Metal- 


Round  off  corners  of  slab 

2  Layers  of  Tar  Paper 


SECTION  OF  EXPANSION-JOINT 

AT  OFFSET  IN  WATERPROOFING  SURFACE 

B 

FIG.  51.— "Unfilled"  Type  of  Waterproofed  Expansion  Joint. 


ing  walls.  They  form  merely  a  weak  bond  in  the  structure,  but 
permit  lateral  movement  and  so  prevent  disalignment.  However, 
unless  some  barrier,  as  a  bituminous  sheet  or  membrane,  is  inter- 
posed, water  will  readily  seep  through  these  joints. 

Fig.  53  shows  a  reinforced  tongue-and-groove  joint  successfully 
used  on  the  Compton  Hill  Reservoir,  St.  Louis,  Missouri.*     The 
*  Engineering  News,  December  23,  1915,  Vol.  74. 


134 


WATERPROOFING  ENGINEERING 


joint  was  filled  with  treated  felt  and  pitch  binder  as  each  section  was 
built  up.  Fig.  54  shows  an  all-adaptable  form  of  joint  waterproofed 
with  a  soft  asphalt  contained  in  a  copper  bulb  the  imbedded  portion 
of  which  is  perforated  so  as  to  bond  more  securely.  Fig.  123  is  an 
efficient  form  of  joint  used  by  the  Delaware,  Lackawanna  & 
Western  R.  R.  on  two  of  its  viaducts. 

Cutoffs  in  Expansion  Joints.  Water  should  not  be  allowed  to 
enter  expansion  joints;  but  if  this  be  inevitable,  then  it  is  best  to 
use  some  form  of  cutoff,  near  one  face  of  the  structure,  and  to  provide 
proper  drainage  within  the  structure.  Copper,  tin,  galvanized  iron, 
lead  and  zinc  sheeting  are  often  used  as  cutoffs  in  expansion  joints, 

A      Clay 


««       • 

Pi        IS 

•fe^v                lliSil 

-  ^| 

^-•M*^*^K;vV 

'}-."^--^-:'  • 

FIG.  52. 

A.  Rectangular  Recess  in  Expansion  Joint,  Filled  with  Plastic  Clay. 

B.  Rectangular  and  Triangular  Tongue-and-groove  Expansion  Joints. 


and  all  serve  their  purpose  very  well,  but  the  copper  sheeting  best  of 
all.  There  are  two  types  of  cutoffs,  known  as  the  internal  and  exter- 
nal. One  of  the  best  illustrations  of  modern  practice  showing  the 
use  of  the  internal  type  of  cutoff  is  in  the  expansion  joints  of  the 
Kensico  Dam  on  the  Catskill  Aqueduct  of  New  York  City. 

The  expansion  joints  in  this  dam  contain  a  strip  of  copper  placed 
across  each  joint  near  the  upstream  face  to  cut  off  leakage  (see  Fig. 
55,  B).  This  cutoff  was  constructed  in  the  following  manner: 
A  portion  of  the  strip  was  placed  in  a  groove  in  the  vertical  face 
of  the  masonry  forming  one  side  of  the  expansion  joint,  and  sur- 
rounded with  concrete  or  mortar,  allowing  the  remainder  of  the 
strip  to  project,  as  shown  in  detail  in  Fig.  55,  A. 


WATERPROOFING  EXPANSION  JOINTS  IN   MASONRY      135 


o'.;;,;. 
:£':•:•: 


O—  %     15  c.  to  c. 


•/.•/'.'?£  -."Expansion  Joint 


r\ 


•^—.  H     Bent  Bars 
.'-.-•  12  "c.  toe. 


^ 


FIG.  53. — Detail  of  Reinforced  Expansion  Joint  for  Retaining  Walls. 


Sidewalk  or 
Road  way  Slab  \ 


^S^'WSttt 

v^VW^f^tei..,. 
:•.:  -• ::.'. : :  .'.'•  ip'orta  pn.'<^'.-.  •'•:  •<{ 

:'&/.:i&y$$&ft?ty&s.:: 
.'.'•:'»:  .•:;.••;  •.'•:j>:.-.'-';'-:-'-"  •'.'."•:'•  •  \ 

^^;  ^::£-'/-^:&':-:-:& 

P13lf;§^lR 

^itfj^y^:!:. 


FIG.  54.— Type  of  Waterproofed  Expansion  Joint  Used  on  the  Brooklyn-Brighton 
Viaduct,  Cleveland,  Ohio. 


136 


WATERPROOFING  ENGINEERING 


WATERPROOFING  EXPANSION  JOINTS  IN   MASONRY      137 

After  the  concrete  or  mortar  in  the  groove  had  set,  the  central 
part  of  the  projecting  strip  and  the  portions  of  the  vertical  faces  of 
the  masonry  against  which  it  rests  were  coated  with  hot  paraffin  or 
other  suitable  substance  to  prevent  the  adhesion  of  the  strip  to 
the  concrete  where  it  crosses  the  expansion  joint.  Concrete  was 
then  placed  and  carefully  rammed  around  the  projecting  strip  on 
the  other  side  of  the  joint,  care  being  taken  to  thoroughly  clean 
the  uncoated  portion  of  the  strip  before  placing  the  concrete.  The 
strips  were  built  up  in  sections,  riveted  together  with  copper  rivets. 

The  operation  of  this  cutoff  is  as  follows:  As  the  masonry 
contracts,  the  expansion  joint  is,  of  course,  enlarged.  Water  enter- 
ing at  D  (Fig.  55,  C)  will  proceed  as  far  as  the  junction  of  the  copper 
strip  E  and  the  masonry.  From  there  the  water  cannot  get  around 


Exterior  of  Pipe  Wall'" 


FIG.  56. — Expansion  Joint  with  Internal  Cut-off  Used  in  Reinforced  Concrete 
Waterpipe.     (Patented.) 

to  the  other  junction  at  F.  Hence,  it  remains  there  and  freezes 
when  cold  weather  sets  in.  The  effect  of  this  freezing  and  the  con- 
sequent thawing  is  cumulative  upon  the  structure  in  that  when 
ice  forms  the  water  expands,  exerting  a  force  in  the  same  direction 
as  the  contraction  of  the  masonry,  caused  by  the  lowering  of  the 
temperature.  On  the  other  hand,  when  thawing  sets  in  the  mobility 
of  the  water  returns  and  the  masonry  expands  unimpeded.  The 
copper  strip  being  placed  near  the  upstream  face  keeps  the  rest  of 
the  joint  practically  dry. 

The  internal  cutoff  is  not  limited  only  to  large  and  massive  struc- 
tures, but  may  be  and  has  been  used  very  successfully  on  reinforced 
concrete  pipes  for  conveying  water  even  under  pressure.  These 
pipes  are  usually  made  in  small  lengths,  3  to  10  feet,  of  scientifically 
graded  aggregate  mixed  in  about  the  following  proportions,  1  :  1J  :  2J. 
The  connection  between  lengths  is  made  in  the  form  of  an  expansion 
joint,  such  as  shown  in  Fig.  56,  which  is  patented.  This  expansion 


138 


WATERPROOFING  ENGINEERING 


joint  has  an  internal  cutoff  in  the  form  of  a  strip  of  soft  copper  cast 
in  the  spigot  end  and  passing  clear  around  the  pipe,  being  crimped 
as  shown  to  permit  the  longitudinal  movement  of  the  sections. 
The  other  end  is  set  in  mortar  rammed  into  the  joint  from  the  inside, 
and  protected  with  a  coat  of  neat  cement,  as  shown.  The  joints 
are  made  free  to  open  and  close  by  the  application  to  the  face  of  the 
spigots  of  a  bituminous  paint. 


-Asphalt  Block  Paving 


Steel  Plate 


Tar  Paper. 

Vitrified  Pipe 
if  required' 


-Vitrified  Pipe 


FIG.  57. — Detail  of  Expansion  Joint  for  Bridge  Floor. 

An  expansion  joint  in  which  the  water  is  not  only  prevented  from 
entering,  but  is  quickly  drained  off  if  it  should  enter,  is  shown  in 
Fig.  57.  This  was  also  used  on  work  connected  with  the  Catskill 
Aqueduct  in  New  York  City.  Fig.  58  shows  another  joint  of  this 
type  (sliding  expansion  joint)  unique  in  its  design,  adapted  to  and 
used  on  the  road  slabs  and  sidewalks  of  the  concrete  arch  bridge  in 
City,  Mo.*  A  similar  joint,  modified  so  that  sliding  is 
*  Engineering  Record,  Vol.  75,  No.  3,  January  20,  1907,  p.  109. 


WATERPROOFING  EXPANSION  JOINTS  IN   MASONRY      139 

obtained  by  means  of  short  pieces  of  old  rails  imbedded  in  the  base 
of  slabs  and  top  of  piers  and  abutments,  was  used  on  a  double- 
track  concrete  railroad  bridge  over  the  Oka w  River  in  Illinois.* 

The  external  cutoff  is  much  used  by  railroad  engineers  for  retain- 
ing walls  and  deserves  a  wider  application  than  it  at  present  enjoys. 
This  cutoff  usually  consists  of  a  fold  formed  by  laying  the  membrane 


1  Layer  Paraffin  Treated 

Felt,  between  2  Layers 

of  Tarred  Felt 


Drainage  Groove 

l"wlde,  2  deep, 

Full  Length  ol  Plates 


ROAD  SUB  EXPANSION   JOINT 


Paint  under  surface  with  hot  asphalt 


x  %'  Bar  2Vc.  to  c. 
--Drainage  Groove 


SIDEWALK  EXPANSION  JOINT 

FIG.  58. — Road  Slab  and  Sidewalk  Waterproofed  Expansion  Joints  Used  in 
Floor  of  Concrete  Arch  Bridge  over  the  Blue  River,  Swope  Park,  Kansas 
City,  Mo. 


of  whatever  material  is  being  used  for  the  waterproofing,  over  a 
1-inch  pipe  at  the  joint  in  the  concrete  to  allow  for  the  expansion 
in  the  structure.  The  pipe  is  removed  after  the  mat  is  completed. 
This  mat  is  then  covered  with  a  protective  coat  of  mortar  or  concrete, 
and  sometimes  with  mastic.  The  external  cutoff  type  of  expansion 
>int  shown  in  Fig.  59  was  designed  by  H.  J.  Finebaum,  engineer, 
*  Engineering  News-Record,  Vol.  80,  No.  8,  February  21,  1918. 


140 


WATERPROOFING  ENGINEERING 


and  used  on  the  new  Hill-to-Hill  bridge  at  Bethlehem,  Penn.*  It 
consists  of  two  pieces  of  copper  held  in  the  concrete  by  lugs  made  by 
bending  back  the  split  ends  of  each  piece  and  placed  on  each  side 
of  the  joint  with  one  end  projecting  through  a  groove  in  the  con- 
crete beyond  the  inside  face  of  the  wall.  These  protruding  ends 
are  then  bent  over  to  hold  a  copper  flashing  piece  across  the  joint 
between  the  sections  of  the  wall.  The  flashing  and  straps  are  then 


No.  It  (Am.  Gage) 
Soft-rolled  Copper 
Straps,  spaced. 
2  ft.  c.  to  <r. 
(Vertically) 


ON  OF  STRAPS  BEFORE  PLACING  OF 
MEMBRANE  WATERPROOFING 


itf 


i« 


'Firs 

of  Fabric,  contii 
at  Expansion  Joint 


Fill 


No.  16  (Am.  Gage) 
Soft-rolled  Copper 
COMPLETED  EXPANSION  JOINT 


FIG.  59. — An  External  Cut-off  Type  of  Expansion  Joint  Used  on  the  new  Hill- 
to-Hill  Bridge  at  Bethlehem,  Penn. 


bound  together,  as  shown,  with  the  waterproofing  fabric,  against 
which  the  fill  is  placed.  A  thin  masonry  protective  cover  would  be 
of  advantage  to  the  waterproofing  fabric.  In  place  of  the  copper 
straps  the  grooves  might  be' filled  with  mortar  with  better  assurance 
of  watertightness. 

Physical-acting  Expansion  Joint  Fillers.     Various  materials  are 
needed  for  filling  expansion  joints  such  as  those  considered  above, 
*  Engineering  News-Record,  Vol.  80,  No.  8,  February  21,  1918. 


WATERPROOFING  EXPANSION  JOINTS  IN   MASONRY      141 

and  their  properties  must  differ  in  accordance  with  the  uses  they 
are  put  to. 

There  are  on  the  market  numerous  expansion-joint  fillers,  but 
comparatively  few  possess  all  of  the  requisite  properties  for  such  a 
material.  The  essential  properties  are  (1)  to  be  chemically  unaf- 
fected by  the  elements;  (2)  to  completely  fill  the  joints  at  all  tem- 
peratures; (3)  to  constantly  adhere  to  the  two  sides  of  the  joint; 
(4)  to  be  elastic,  plastic  and  cohesive  at  climatic  temperatures. 

As  with  many  waterproofing  materials  so  with  many  expansion- 
joint  fillers,  their  composition  is  usually  kept  secret  and  carefully 
guarded,  even  from  the  purchaser.  Therefore  the  only  assurance 
one  has  of  obtaining  the  right  materials  is  the  selling  companies7 
guarantee;  or  else  the  architect,  engineer  or  contractor  must  resort 
to  chemical  analyses  and  physical  tests,  and  though  these  tests  are 
quite  expensive,  it  is  the  safest  way.  On  large  engineering  work 
this  is  very  important  and  on  building  construction  quite  essential. 

In  this  connection  it  is  of  material  interest  to  know  that  the 
chief  cause  of  failure  of  joint  fillers  is  loss  of  their  sticky  condition. 
This  occurs  for  the  following  reasons:  (1)  Evaporation  of  solvents 
with  the  consequent  hardening  of  the  material;  (2)  loss  of  light  oils 
due  to  capillary  action  with  the  consequent  decrease  in  volume  of 
the  material ;  (3)  leading  on  of  water-soluble  material  with  the  conse- 
quent porosity  of  the  joint  fillers;  (4)  chemically  unstable  material 
with  the  consequent  decay  of  the  joint  filler.  A  material  that  is 
immune,  at  least  for  several  years,  from  the  ravages  of  these  four 
agents  makes  an  ideal  joint  filler. 

It  is  common  knowledge  that  such  materials  as  tar  compounds 
and  blown  asphalts*  are  extensively  used  and  make  good  expansion 
joint  fillers  for  many  purposes.  But  their  indiscriminate  use  in  the 
past  was  followed  by  many  failures.  Investigation  beforehand 
would  have  obviated  these  disappointments.  It  would  have  dis- 
closed the  fact  that  many,  tar  compounds  (made  for  this  purpose) 
leach  out  all  too  soon,  and  that  blown  asphalts  are  but  short-lived 
when  exposed  to  the  elements.  Various  putties  are  used  as  joint 
fillers,  but  unless  the  liquid  part  is  of  such  nature  and  consistency 
that  it  will  not  evaporate  or  be  absorbed,  these  mixtures  will  harden 
and  shrink,  as  will  also  those  containing  animal  and  vegetable 
materials.  Hence  the  necessity  for  thorough  testing  of  these 
products. 

*  Refined  asphalts  acted  upon  by  steam  or  air  infused  through  its  mass,  which 
process  produces  a  certain  amount  of  oxidation  in  the  asphalt,  resulting  in  greater 
toughness  of  the  product. 


142  WATERPROOFING  ENGINEERING 

A  commonly  used  joint  filler  for  joints  between  steel  and  con- 
crete (such  joints  usually  being  shaped  like  a  "  V,"  or  sometimes 
rectangular)  is  a  good  grade  of  medium  hard  refined  asphalt,  mixed 
with  from  5  to  10  per  cent  of  grahamite,  depending  upon  the  melting- 
point  desired  for  the  final  product.  Such  a  mixture  is  tough,  rub- 
bery and  durable.  At  ordinary  temperatures  it  is  hard,  but  elastic. 
In  applying  this  compound,  it  must  be  melted  and  poured  into  or 
mopped  over  the  joints. 

Bituminous  mastics  are  also  much  used  for  filling  V-joints  and 
for  roof  flashings  with  good  results.  These  are  usually  made  of 
medium-consistency  coal-tar  pitch  or  asphalt,  mixed  with  about  20 
per  cent  of  cement  or  limestone  dust  and  asbestos.  A  mixture  of 
about  45  per  cent  pine-tar  pitch,  30  per  cent  of  petroleum  oil  and  25 
per  cent  of  fiber  asbestos,  is  another  extensively  used  filler  for  the 
same  purpose. 

For  certain  types  of  concrete  structures  such  as  retaining  and 
abutment  walls,  a  mixture  of  clay  and  oil  in  various  proportions  is 
sometimes  used  as  an  expansion  joint  filler.  The  vertical  joint  in 
these  structures  is  usually  a  plane  of  weak-bond  with  an  enlarged 
space  near  the  back  of  the  wall  shaped  either  as  a  rectangle  or  a 
triangle,  and  it  is  in  this  space  that  the  joint  filler  is  placed.  The 
rest  of  the  joint  is  closed  up  by  the  insertion  of  from  one  to  three 
plies  of  treated  felt,  usually  nailed  to  the  face  of  the  green  concrete, 
and  against  which  the  new  concrete  is  poured  in  forming  the  wall. 
The  specific  object  of  the  joint  filler  is  to  intercept  any  percolation 
of  water  along  the  joint. 

Another  joint  filler  usable  for  the  same  purpose  and  also  for 
roof  flashings,  is  composed  of  coal  tar  and  powdered  slate,  in  equal 
parts  by  weight.  This  mixture  is  applied  cold  with  a  trowel. 

The  following  compounds  are  very  serviceable  for  filling  hori- 
zontal joints  in  masonry  because  they  remain  elastic  at  comparatively 
low  temperatures.  However,  all  the  bituminous  fillers  must  be 
completely  encased,  as  they  have  a  constant  though  imperceptible, 
flowing  tendency,  and  will  actually  flow  away  in  time  unless  pre- 
vented. Many  expansion-joint  failures  are  traceable  to  the  neglect 
of  guarding  against  this.  The  degree  of  hardness  for  all  bituminous 
joint  fillers  is  based  on  climate  and  local  conditions.  Usually  these 
types  of  joint  fillers  also  require  preheating  and  pouring  during 
application. 

(1)  A  Mexican  petroleum  of  about  18  deg.  to  21  deg.  Baume, 
refined  so  as  to  leave  the  heavier  oils  with  the  basic  asphalt,  then 
blown  with  compressed  air  until  it  has  a  melting-point  of  about  175 


WATERPROOFING  EXPANSION  JOINTS  IN   MASONRY      143 

deg.  Fahr.  (79.5  deg.  Cent.)  by  the  Cube-in-water  method.  To 
apply  this  material  it  must  be  heated  and  poured  into,  or  mopped 
over,  the  joint. 

(2)  Any  good-grade  refined  asphalt  of  medium  consistency  to 
which  is  added  about  5  per  cent  of  stearin  pitch  and  then  boiled 
down  to  a  dense  consistency.     This  material  is  melted  and  poured 
into  the  joint  when  applied. 

(3)  A  blown  refined  Mexican  asphalt  mixed  with  about  3  per  cent 
of  gilsonite.     The  asphalt  used  in  making  this  mixture  should  melt 
at  about  140  deg.  Fahr.  (60  deg.  Cent.)  by  the  Cube-in-water  method, 
and  the  mixture  at  about  175  deg.  Fahr.,  by  the  same  method.     The 
kind  of  asphalt  used  governs  the  percentage  of  gilsonite  to  be  added ; 
for  example,  a  California  asphalt  would  require  about  10  per  cent 
gilsonite.     The   amount   also   depends   on   the   climate   and   local 
condition  of  the  work. 

(4)  A  refined  Trinidad  asphalt  having  a  melting-point  of  about 
200  deg.  Fahr.  by  the  Cube-in-water  method,  88  per  cent;  gilsonite  7 
per  cent;  and  grahamite  5  per  cent.     This  mixture  is  especially  ap- 
plicable to  warm  climates. 

(5)  Any  good-grade  refined  asphalt  of  medium  consistency,  80 
per  cent;   linseed  or  China  wood  oil  10  per  cent;   and  fine  mineral 
matter  (but  no  sand)  10  per  cent. 

(6)  A  petroleum  residuum  in  the  form  of  a  grease  (petrolatum), 
for  instance,  and  free  of  light  or  volatile  oils  makes  one  of  the  best 
joint  fillers  for  V-joints  of  the  type  shown  in  Fig.  129. 

Chemical-acting  Joint  Fillers.  Chemical  joint  fillers,  that  is, 
those  compounds  that  become  operative  only  after  chemical  action 
has  proceeded  in  their  substance  while  embedded  in  the  joint,  are 
not  really  expansion-joint  fillers.  But  they  are  considered  here 
because  they  are  a  means  of  making  watertight  joints  in  engineering 
structures. 

For  calking  joints  in  steel  and  iron  tunnels,  especially  those  of 
the  segmental  type  (see  Fig.  136) ,  materials  of  the  following  formulas 
have  been  found  serviceable. 

(1)  Powdered  pig  iron,  mixed  with  half  as  much  lime,  a  quarter 
as  much  of  powdered  sand,  and  about  one-eighth  as  much  of  salam- 
moniac.     This  gives  a  hard,  waterproof,  joint  filler. 

(2)  Eighty  parts  fine  iron  borings,  one  part  salammoniac,  two 
parts  flour  of  sulphur,  all  by  weight  and  mixed  to  a  paste.     This 
mixture  forms  a  quick-setting  joint  filler.* 

(3)  The  following  mixture  is  a  slow-setting  joint  filler:    Two 

*  Molesworth's  Pocket  Book  of  Engineering. 


144  WATERPROOFING  ENGINEERING 

hundred  parts  fine  iron  borings,  two  parts  salammoniac,  one  part 
flour  of  sulphur,  all  by  weight  and  mixed  to  a  paste.  This  is  prefer- 
able to  the  former,  if  the  joint  is  not  to  be  put  into  use  immediately. 

(4)  A  rust  joint  can  be  made  by  mixing  ten  parts  of  iron  filings 
and  three  parts  of  chloride  of  lime  to  a  paste  with  water.     This 
material,  when  applied  to  the  joint,  will  harden  in  about  twelve  hours. 

(5)  For  some  time  past  steel  joints  have  been  made' watertight 
by  the  application  of  a  paste  composed  of  powdered  pig  iron  and 
water  only.     But  an  accelerative  oxidizing  agent  is  now  usually 
added  and  preferred. 

The  joints  of  steel  tanks  and  all  manner  of  steel  and  iron  con- 
struction where  rigidity  is  practically  a  property  of  the  structure 
can  be  made  watertight  by  properly  calking  with  a  steel  calking 
chisel  (see  Fig.  115).  In  fact,  this  is  the  common  and  very  successful 
practice  at  present.  Lead  wool,  introduced  a  few  years  ago,  has 
been  successfully  used  without  oakum  on  similar  work,  and  in  special 
cases,  as  when  used  for  calking  joints  in  structural  steel  work  where 
watertightness  is  an  essential  feature  of  the  structure. 

It  is  often  necessary  to  make  floor  joints  of  buildings  watertight 
so  as  to  prevent  leakage  and  consequent  defacement  of  the  ceiling 
below  when  the  floor  above  it  is  washed.  A  compound  well  adapted 
for  filling  such  joints,  and  for  filling  knot  holes  in  wooden  floors 
and  for  other  similar  purposes,  is  made  of  five  parts  of  fresh  cheese 
(the  so-called  Dutch  or  cottage  cheese),  one  part  of  unslaked  or  pul- 
verized lime,  both  by  volume,  kneaded  together  to  a  stiff  dough. 
This  mixture  becomes  stone-hard,  and  is  insoluble  in  water.  By 
the  addition  of  mineral  colors,  such  as  raw  or  burnt  sienna  or  umber, 
yellow  or  red  ochre,  Venetian  or  Indian  red,  this  putty  can  be  colored 
to  any  desired  shade.* 

*  '739  Paint  Questions  Answered,"  published  by  the  Painter's  Magazine 
of  New  York,  1904. 


CHAPTER  V 
WATERPROOFING   MATERIALS 

Selection  and  Adaptability  cf  Materials.  There  are  on  the 
market  numerous  waterproofing  materials,  but  comparatively  few 
are  extensively  used.  We  shall  examine  the  most  important  of 
them,  however,  to  determine  their  general  properties  whence  we  will 
be  able  to  better  understand  their  use  and  adaptability  for  the 
different  systems  of  waterproofing  in  which  they  are  employed. 
The  system  of  waterproofing  and  the  method  of  application  usually 
determine  the  character  or  kind  of  material  to  be  used,  while  both 
the  material  and  the  system  of  waterproofing  are  dependent  on  the 
type  of  structure  to  be  waterproofed.  For,  obviously,  an  existing 
structure  presents  different  conditions  and  waterproofing  possi- 
bilities from  one  in  the  course  of  construction.  Again,  a  tunnel  or 
subway  presents  different  conditions  and  difficulties  than  does  a 
building  or  bridge.  Hence  the  need  for  different  waterproofing 
systems,  methods  and  materials.  Of  course,  where  several  materials 
are  equally  good,  or  methods  equally  applicable,  then  cost  governs. 
A  low  first  cost,  however,  is  not  necessarily  the  most  economical,  and 
it  behooves  the  architect,  engineer  and  contractor  to  be  calculating 
and  cautious  in  this  regard. 

Materials  for  Different  Systems  of  Waterproofing.  Nearly  all 
waterproofing  materials  readily  fall  under  the  six  systems  of  water- 
proofing previously  considered,  namely:  (1)  "  surface  coating"; 
(2)  "membrane";  (3)  "  mastic";  (4)  "  integral";  (5)  "  self- 
densified  concrete  ";  (6)  "  grouting  process." 

Each  system  however,  has  certain  materials  best  adapted  to 
itself  as,  for  example,  in  the  "surface  coating"  system,  are  used: 

(a)  Scores  of  patented  and  secret  compounds. 

(6)  Coatings  of  elaterite,  paraffin  (oil  and  solid),  mastic,  tar, 
asphalt,  and  mixtures  of  these,  cement,  cement  grout,  neat  cement, 
and  mixtures  of  caustic  potash  or  soap  and  alum. 

(c)  Paints  composed  cf  suet,  lime,  asphalts  dissolved  in  naphtha, 
in  benzine  or  mixed  with  linseed  oil,  and  other  hydrocarbons. 

(d)  Enamels  consisting  of  mixtures  of  linseed  oil  and  rosin  or 

145 


146 


WATERPROOFING  ENGINEERING 


bitumen;    solutions  of  bakelite,  and   proprietary  bituminous   com- 
pounds. 

In  the  membrane  system  are  mainly  used: 


a.  Bitumens 


6.  Sheetings 


c.  Metals 


Natural  (refined). 

Asphalt      Artificial  (Asphalt-petroleum  residuum). 
Proprietary. 

f  Coal-tar. 
Pitch*         Oil-tar. 

I  Proprietary. 

Asphalt  saturated  felts,  papers  and  fabricsf 
Coal-tar  pitch  saturated  felts,  papers  and  fabrics. 
Oil-tar  pitch  saturated  felts,  papers  and  fabrics. 
Saturated  asbestos-felts,  asbestos-covered  sheet  metal. 

Plate  steel. 

Cast  steel. 

Cast  iron. 

Sheet  lead,  sheet  tin,  sheet  copper,  sheet  iron. 


In  the  mastic  system  are  used :    . 

(a)  Coal-tar  pitch  sheet  mastic,  asphalt  sheet  mastic. 

(6)  Brick-in-mastic  courses,  tile-in-mastic  courses. 

In  the  "  integral  "  system  are  used: 

(a)  Scores  of  patented  and  secret  compounds. 

(6)  Fattening  and  void-filling  materials,  such  as  hydrated  lime, 
colloidal  clay,  mixtures  of  iron  and  salammoniac,  stearin  and  stearates, 
gelatinous  and  bituminous  compounds,  powdered  calcium  minerals, 
and  combinations  of  some  of  these;  also,  graphite  and  petroleum  oils. 

In  "  self-densified  concrete"  are  used:  (a)  All  the  well-known 
mineral  aggregates,  as  stone,  gravel,  sand  and  cement,  plus  experi- 
enced labor  and  careful  supervision. 

In  the  "  grouting  process  "  are  used: 

(a)  Patented  and  special  cements. 

(6)  Portland  or  natural  cements  (either  as  neat  cement,  or  with 
sand  as  grout,  and  either  wet  or  dry) . 

All  of  the  above  materials  may  again  be  approximately  grouped 
under  the  general  terms  of  "  chemical  "  — and  "  mechanical  "•  -  act- 

*  Pitch  is  a  general  term  including  asphalts  and  many  other  substances  of  a 
hydro-carbon  nature,  but  by  usage  in  the  waterproofing  field  has  come  to  be 
regarded  as  the  designation  of  coal-tar  products,  especially  coal-tar  pitch. 

|  Fabrics  include  Jute,  Paper  and  Cotton  (Burlaj)),  also  Cotton  drill. 


WATERPROOFING  MATERIALS  147 

ing  materials  depending  on  whether  they  act  directly  or  indirectly 
as  waterproofing  agents,  i.e.,  whether  they  act  through  a  chemical 
or  mechanical  change  or  adaptation,  either  in  their  own  structure 
or  the  body  of  the  concrete.  This  is  not  always  certain  or  easy  to 
determine,  but  the  following  division  is  sufficiently  correct  for  all 
practical  purposes. 

(a)  Materials  acting  chemically  as  waterproofing  agents: 
Soap,  alum,  caustic  potash,  suet,  stearin  and  stearates,  rosin, 
calcium,  minerals,  linseed  oil,  lime,  hydrated  lime,*  salammoniac, 
powdered  iron,  Portland  cement,  natural  cement,  Puzzalon  cement, 
sand  cement  and  neat  cement. 

(6)  Materials  acting  mechanically  as  waterproofing  agents: 
Paraffin,  asphalt,  elaterite,  gilsonite,  grahamite,  tar,  bakelite, 
coal-tar  pitch,  oil-tar  pitch,  mastic,  bituminous  paints,  colloidal  clay, 
graphite,  gasoline,  benzine,  naphtha;  treated  paper,  paper  burlap; 
treated  asbestos  felt,  treated  rag  and  pulp  felt,  jute  burlap,  fabric, 
cotton  drill;  cast  ironx  plate  steel  and  all  sheet  metal,  water,  sand, 
gravel,  stone,  cement  grout  and  cement  coatings. 

NATURE  OF  MATERIALS  ACTING  CHEMICALLY  AS  WATERPROOFING 

AGENTS 

A  certain  amount  of  knowledge  regarding  the  nature  of  these 
materials  is  essential  to  the  proper  understanding  of  their  use  and 
application  in  the  art  of  waterproofing.  It  was  therefore  deemed 
expedient  to  make  the  following  notes  relating  to,  and  affecting 
their  use  in  waterproofing  engineering.  It  is  not  intended  that  these 
remarks  be  exhaustive,  but  merely  explanatory  of  the  properties 
and  uses  of  the  more  important  materials. 

Alum.  Common  alum  is  a  white  powder  or  crystalline  substance 
consisting  of  a  double  sulphate  of  aluminum  and  potassium.  It  is 
found  native  as  kalinite  and  manufactured.  It  is  soluble  in 
boiling  water  in  equal  parts  by  weight,  but  only  about  5  per  cent 
in  water  at  60  deg.  Fahr.  (15.5  deg.  Cent.).  In  the  form  of  a  solu- 
tion it  is  brushed  on  a  masonry  or  concrete  surface  over  a  previous 
coat  of  soap  solution  with  which  it  combines  chemically  forming  a 
stearate  of  aluminum  which  acts  as  a  void-filler  and  also  forms  a 
water-repellent  coating. 

Calcium  (compounds).  Calcium  is  a  lustrous,  white,  very  duc- 
tile, and  malleable  metal  about  as  hard  (and  scarce  in  the  pure  form) 
as  pure  gold.  It  has  the  peculiar  property  of  decomposing  water 
*  Also  acts  in  part  at  least  as  an  inert  void-filler. 


148  WATERPROOFING  ENGINEERING 

with  evolution  of  hydrogen.  Calcium  compounds,  are  salts  of 
calcium  and  it  is  these  that  are  used  in  waterproofing.  They  occur 
largely  diffused  in  nature  in  the  form  of  chalk,  marble,  limestone, 
coral,  etc.  As  calcium  sulphate  or  calcium  carbonate  (marble) 
it  is  used  in  powder  form  in  the  manufacture  of  dampproof  paints. 
These  compounds  when  mixed  with  cement  and  aluminum,  form 
many  secret  (?)  waterproof  and  dampproof  surface-coating  com- 
pounds. 

Casein.  Casein  is  an  albumen  found  in  the  milk  of  animals. 
When  milk  curdles  it  is  due  to  the  coagulation  of  the  casein  present, 
which  averages  about  3  per  cent.  Acetic  acid  or  a  bit  of  rennet 
will  produce  curdling  and  the  casein  separates  as  curd.  Casein 
is  not  easily  affected  by  heat.  When  moist  and  fat-free,  it  forms 
insoluble  precipitates  with  quicklime,  borax  or  strong  sodium  silicate 
solutions.  In  any  of  these  forms  it  is  used  as  a  waterproofing  cement. 

Caustic  Potash.  Potassium  hydroxide  is  commonly  called 
caustic  potash.  It  is  a  white,  solid  substance,  very  easily  melted 
and  quite  soluble  in  water  or  alcohol.  In  solution  it  possesses,  in  the 
very  highest  degree,  the  properties  termed  alkaline.  In  water- 
proofing it  is  sometimes  substituted  for  soap  as  a  surface  coating, 
or  it  is  used  with  various  chemicals  in  secret  (?)  waterproofing 
compounds. 

China  Wood  Oil.  China  wood  oil  is  obtained  from  the  seeds 
of  the  fruit  that  grows  on  the  wood  oil  tree  of  the  Aleurites  species 
of  China  and  Japan.  These  trees  are  of  comparatively  rapid  growth, 
with  trunks  of  light,  soft  wood.  The  oil  is  a  rapid  drying  one  and 
is  largely  used  in  the  manufacture  of  varnish  and  waterproof  cements. 
It  is  often  advantageously  substituted  for  linseed  oil  in  the  manu- 
facture of  some  waterproof  paints  and  varnishes.  It  is  slightly 
heavier  than  the  boiled  or  raw  linseed  oil,  its  specific  gravity  being 
0.944. 

Hydrated  Lime.  Hydrated  lime  is  a  finely  divided  white  powder 
made  of  ordinary  lime  by  the  addition  of  just  sufficient  water  to 
insure  complete  slaking,  and  so  that  the  heat  generated  will  evaporate 
all  the  excess  water,  leaving  the  product  dry.  There  are  several 
grades  made,  the  difference  being  mainly  in  the  calcium  and  mag- 
nesium content;  but  this  is  dependent  on  the  source  of  the  carbonate. 
High  magnesium  lime,  though  it  slakes  and  sets  slower,  is  superior 
in  other  important  properties  to  the  high  calcium  limes.  For 
ordinary  purposes  hydrated  lime  is  used  for  and  in  precisely  the 
same  way  as  common  lime.  In  waterproofing  it  is  used  to  a  greater 
extent  than  common  lime  as  it  is  much  more  effective,  because  when 


WATERPROOFING   MATERIALS  149 

properly  manufactured,  it  slakes  and  mixes  more  thoroughly  in  the 
concrete  (see  Chapter  III). 

Iron  (Powdered).  Iron  is  an  element  abundant  in  nature  and 
universal  in  its  existence  and  application.  For  waterproofing  pur- 
poses pig  iron  is  used  in  granulated  or  powdered  form.  When  mixed 
with  appropriate  chemicals,  as,  for  instance,  salammoniac,  sulphur 
and  even  cement,  it  forms  a  surface-hardening  substance  for  concrete 
and  mortar.  When  mixed  with  water,  it  forms  and  is  often  used  as 
a  "  rust  joint."  In  this  manner  it  is  sometimes  used  in  calking 
joints  in  cast-iron  tunnel  linings.  It  can  readily  be  tempered  in  its 
oxidizing  action  by  mixing  it  with  Portland  cement. 

Lime.  Lime  is  a  white  substance  resulting  from  the  burning 
of  limestone  in  kilns  until  the  carbon  dioxide  is  driven  off  as  a  gas, 
leaving  the  calcium  oxide,  or  lime,  which  slakes  when  water  is  added 
to  it.  On  exposure  to  the  air  it  sets  and  hardens,  by  reverting  to 
its  original  state,  i.e.,  it  takes  in  carbon  dioxide  from  the  atmosphere. 
It  is  often  incorporated  in  concrete  and  mortar  to  reduce  their 
porosity,  or  mixed  with  certain  salts  in  cement  mortar  to  form  a 
waterproof  mortar  coat.  But  its  benefits  are  limited  as  well  as  its 
use,  because  it  will  not  set  under  water. 

Linseed  Oil.  Linseed  oil  is  obtained  from  the  seed  of  flax  either 
by  pressing  or  by  extraction  with  naphtha  or  other  solvents.  It  is 
used  either  raw  or  boiled;  the  boiled  toughens  or  dries  quicker  in 
air.  The  unadulterated  linseed  oil  possesses  a  characteristic  but 
disagreeable  taste  and  odor.  Its  color  is  light  amber  or  greenish 
yellow.  The  boiled  oil  dries  more  rapidly  on  exposure  to  the  air 
than  the  unboiled  and  is  mostly  used  for  interior  work,  the  raw  for 
exterior  work.  Both  kinds  thicken  and  toughen  with  time,  and  dry 
by  oxidation,  i.e.,  they  have  the  property  of  absorbing  oxygen  and 
forming  a  tough  and  elastic  substance  which,  however,  eventually 
deteriorates.  It  is  often  used  to  flux  asphalt  and  coal-tar  pitch, 
to  make  surface  coatings  for  dampproofing  and  waterproofing 
purposes. 

Natural  Cement.  Natural  (or  Roman)  cement  is  a  very  fine 
powder,  made  from  clinkers  resulting  from  the  burning,  at  a  com- 
paratively low  temperature,  of  an  impure  limestone,  containing  from 
15  to  40  per  cent  of  silica,  alumina  and  iron  oxide.  It  was  first 
manufactured  in  England  in  1796  by  James  Parker.  This  cement  is 
comparatively  slow  setting  and  is  not  as  widely  used  as  Portland 
cement.  Neither  is  it  as  reliable,  because  the  proportions  vary 
not  at  will,  but  according  to  the  nature  of  the  source.  It  is  not 
generally  used  where  a  very  impervious  concrete  is  desired. 


150  WATERPROOFING  ENGINEERING 

Neat  Cement.  Neat  cement  is  a  term  applied  to  a  paste-like 
mixture  of  cement  and  water  regardless  of  proportions.  It  is 
applicable  to  any  kind  of  masonry  both  above  and  below  ground 
surface  in  the  form  of  a  thin  coat  or  surface  wash.  The  thicker  the 
coat  however,  the  more  impermeable  it  is  and  hence  the  more  effec- 
tive as  a  waterproofing  agent.  Neat  cement  is  often  used  for  grout- 
ing purposes  especially  where  rock  seams  or  cracks  are  small  but 
extensive. 

Portland  Cement.  Portland  cement  (named  for  its  resemblance, 
when  set,  to  limestone  quarried  at  Portland  Isle,  England,  where  it 
was  first  made  in  1811,  and  patented  by  Joseph  Aspdin,  a  bricklayer, 
of  Leeds,  England,  in  1824),  is  a  very  fine  powder  made  from  clinkers 
resulting  from  the  burning,  at  a  temperature  of  about  3000  deg. 
Fahr.  (1649  deg.  Cent.),  of  a  finely  ground  artificial  mixture  of  lime, 


FIG.  60. 

A.  Cement  Rock,  as  it  Appears  in  Nature. 

B.  Cement  Materials  being  Burned  in  Rotary  Kilns. 

C.  Cement  Clinker  as  it  Comes  from  the  Kilns. 

D.  Cement,  Ground  Fine  for  Use. 

silica,  alumina  and  iron  oxide  in  certain  definite  proportions  (see 
Fig.  60).  This  combination  is  made  by  mixing  limestone  or  marl 
with  clay  or  shale  in  the  proportions  of  about  three  to  one  respec- 
tively. The  finer  the  cement  the  more  impervious  is  the  concrete 
made  with  it.  Most  concrete  construction  is  done  with  Portland 
cement. 

Puzzolan  Cement.  Puzzolan  cement  is  a  mechanical  mixture 
of  powdered  slaked  lime  with  either  a  volcanic  ash  or  a  blast  furnace 
slag.  In  the  form  of  a  mixture  of  powdered  slaked  lime  and  volcanic 
ash,  puzzolan  cement  was  first  used  by  the  Romans  in  their  building 
construction.  Unlike  the  other  cements,  this  mixture  is  not  burned 
but  is  finely  ground.  The  resulting  powder  is  somewhat  superior 


WATERPROOFING  MATERIALS  151 

to  other  cements  in  its  resistance  to  the  action  of  sea  water,  for 
which  reason  it  is  often  used  in  maritime  construction. 

Resin.  Resin  is  a  solid  or  semi-solid  substance  composed  of 
carbon,  oxygen  and  hydrogen,  mainly  of  dark  amber  color,  homo- 
geneous and  translucent,  though  some  varieties  are  colorless  and 
transparent.  It  is  mostly  of  vegetable  origin.  Common  rosin 
is  a  similar  substance  remaining  when  turpentine,  from  gum  or  pine 
resin,  is  distilled  until  the  water  and  volatile  oils  are  expelled.  Resin 
is  insoluble  in  water  but  soluble  in  alcohol,  ether  and  various  oils. 
Rosin  is  used  extensively  as  a  flux  in  inexpensive  paints,  varnishes, 
dampproofing  and  roofing  compounds  in  which  it  acts  as  a  filler 
and  for  making  soap.  Nearly  all  surface  coating  compounds  con- 
tain resin  or  rosin,  where  it  is  often  used  as  an  adulterant  and  tends 
to  make  the  compound  brittle. 

Salammoniac.  Salammoniac  (NH4-C1)  is  ammonium  chloride, 
a  white  crystalline  substance,  obtained  from  the  ammoniacal  waters 
of  gas  works  by  adding  sulphuric  acid  and  then  sublimating  the  sul- 
phate thus  formed  with  sodium  chloride,  or  by  absorbing  ammonia 
gas  in  hydrochloric  acid,  also  by  heating  ammonium  sulphate  with 
common  salt.  It  is  freely  soluble  in  cold  water,  but  much  more  so  in 
hot  water.  In  waterproofing  it  is  mainly  used  as  an  oxidizing  agent, 
particularly  for  powdered  iron,  with  which  it  is  often  mixed  for  calk- 
ing joints  in  steel  and  iron-lined  tunnels,  and  in  modified  form  for 
hardening  concrete  surfaces,  which  tends  to  make  these  surfaces 
water  tight  and  dustproof. 

Sand-cement.  Sand-  or  silica-cement  is  a  mechanical  but  inti- 
mate mixture  of  Portland  cement  with  a  pure  clean  sand,  very  finely 
ground  together.  In  the  best  grade  of  sand-cement  the  proportions 
of  cement  to  sand  are  1  :  1  but  as  lean  a  mixture  as  1  :  6  has  been 
made.  This  cement,  efficiently  proportioned,  has  been  and  may  well 
be  used  for  making  impervious  concrete,  providing  the  equally 
important  matters  of  grading  and  mixing  are  properly  attended  to.* 

Soap.  Soaps  are  metallic  salts  of  the  higher  fatty  acids  or,  more 
particularly,  compounds  formed  by  the  substitution  of  the  alkalies, 
sodium  and  potassium,  or  magnesium  and  aluminum  for  the  glycerine 
in  common  fats.  Soaps  containing  sodium  harden  on  exposure  to 
the  air  and  are  known  as  hard  soaps,  and  those  containing  potassium 
absorb  water  under  the  same  conditions  and  tend  to  liquefy,  hence 
they  are  known  as  soft  soaps.  The  sodium  and  potassium  soaps 

*  It  is  of  course  beyond  the  scope  of  this  book  to  discuss  in  detail  the  respective 
properties  of  cements.  Further  and  full  information  will  be  found  in  any  stand- 
ard book  on  concrete. 


152  WATERPROOFING  ENGINEERING 

are  water-soluble,  the  magnesium  and  aluminum  soaps  are  water- 
insoluble.  In  waterproofing  the  -soaps  are  used  (1)  by  being  dis- 
solved in  water  and  the  solution  brushed  on  a  concrete  or  other 
masonry  surface  and  then  coated  with  an  alum  solution  with  which 
it  unites  chemically  forming  an  insoluble  stearate  (soap)  of  aluminum 
which  acts  as  a  void  filler  and  water  repellent;  (2)  by  being  suitably 
mixed  with  colloidal  matter  it  is  often  incorporated  in  concrete  to 
aid  in  increasing  its  density.  Castile  soap  is  most  generally  used  in 
making  soap  solutions,  but  any  of  the  common  soaps  in  everyday 
use  may  also  be  used.  Aluminum  soaps  are  used  for  making  various 
proprietary  integral  waterproofing  compositions. 

Stearate.  Stearate  is  a  salt  of  stearic  acid.  Stearates,  such  as, 
for  example,  ammonium  stearate  or  lime  stearate,  are  used  as  integral 
waterproofing  compounds.  They  have  the  consistency  of  hard 
soap  and  are  mostly  insoluble  in  water  but  are  decomposed  by  most 
acids.  Ammonium  stearate  can  be  made  by  taking  stearic  acid  and 
combining  it  with  ammonium  hydroxide  in  the  presence  of  con- 
siderable water  or  water-yielding  material.  This  forms  a  more 
or  less  air-unstable  quasi-soap  of  a  water-soluble  nature.  This 
soap-like  material,  when  brought  in  contact  with  cement  in 
the  presence  of  moisture,  reacts  and  forms  a  water-insoluble 
stearate,  with,  water  shedding  properties,  while  the  alkali,  that  is, 
the  ammonia,  being  liberated  as  a  volatile,  supposedly  disappears 
in  time. 

Stearic  Acid.  Stearic  acid  is  a  derivative  product  of  the  more 
solid  fats  of  the  animal  kingdom  and  vegetable  fats,  especially  those 
of  cacao-beans,  and  certain  African  nuts.  It  is  prepared  from  mutton 
suet  or  cacao  fat  by  saponifying*  the  fat  with  soda-lye.  Pure  stearic 
acid  has  a  specific  gravity  of  1.00  at  50  deg.  Fahr.  (10  deg.  Cent.). 
It  melts  at  156  deg.  Fahr.  (69  deg.  Cent.)  to  a  colorless  oil,  which 
cools  into  a  solid,  white  scaly  mass.  It  is  insoluble  in  water  and  is 
much  used  for  making  dampproofing  varnishes  and  integral  water- 
proofing compounds. 

Stearin.  Stearin,  a  solid  substance  at  ordinary  temperatures, 
is  the  chief  ingredient  of  suet  and  tallow.  Stearic  acid  is  obtained  from 
it  by  the  application  of  steam  to  the  harder  fats,  and  chemical 
treatment.  Stearin  is  used  for  making  various  waterproofing 
materials,  and  is  often  mixed  with  asphalt  to  make  proprietary  joint- 
filling  compounds. 

*  Saponification  is  the  process  by  which  the  fatty  acids  and  glycerine  are 
separated  with  the  latter  set  free;  that  is,  the  process  of  converting  a  fat  or  oil 
into  a  soap  by  combination  with  an  alkali. 


WATERPROOFING   MATERIALS  153 

Stearin  Pitch.  Stearin  pitch  is  an  animal  by-product  obtained 
from  stearic  acid  in  the  manufacture  of  candles.  It  is  used  as  a 
coating  for  some  smooth-surfaced  ready  roofings,  and  is  a  very 
stable  material,  being  practically  unaffected  by  the  action  of  the  sun. 

Suet.  Suet  is  animal  fat,  especially  the  harder  and  less  fusible 
fat  about  the  kidneys  and  loins,  and  whose  chief  ingredient  is  stearin. 
It  is  cheap  and  when  chemically  treated  is  used  as  a  water-repellent 
for  mass  concrete.  When  mixed  with  colophony  in  certain  propor- 
tions it  is  used  as  a  dampproofing  and  as  a  water-repellent  varnish. 

NATURE  OF  MATERIALS  ACTING  MECHANICALLY  AS  WATERPROOFING 

AGENTS 

Asbestos.  Asbestos  is  a  fibrous  mineral  (see  Fig.  61,  A,  B) 
derived  from  certain  igneous  and  metamorphic  rocks  (by  the  action 


FIG.  61. 

A.  Asbestos  as  it  Comes  from  the  Mines. 

B.  Asbestos  Fiber  as  Used  with  Bitumen  to  Form  Plastic  Compounds. 

of  heated  waters,  in  nature)  and  is  chemically  known  as  a  hydrous- 
magnesium  silicate.  Commercially  asbestos  has  been  used  since 
ancient  times,  but  its  discovery  is  attributed  to  the  Romans.  It  is 
incombustible  and  non-perishable  and  because  of  its  fibrous  nature 
is  often  incorporated  in-  various  bitumens  to  form  a  plastic  water- 
proofing cement.  It  is  also  powdered,  and  in  this  form  it  is  used  as 
a  filler  in  dampproofing  paints.  It  is  also  used  for  making  asbestos 
felt  which  is  often  saturated  in  the  same  manner  as  roofing  felt 
and  also  used  for  the  same  purpose.  As  such  it  is,  however,  much 
more  expensive.  It  is  also  made  into  roof  shingles. 

Asbestos  Felt.  Asbestos  felt  is  made  of  about  95  pier  cent  asbestos 
with  some  form  of  sizing  to  permit  its  being  rolled  into  long  thin 
sheets  of  various  widths  and  thicknesses  similar  to  roofing  felt.  It 


154  WATERPROOFING  ENGINEERING 

is  weaker  than  the  ordinary  felts,  does  not  saturate  as  well,  and  has 
not  as  wide  an  application,  but  it  will  not  decay  and  is  fireproof 
while  the  felts  and  fabrics  are  not.  This  latter  property  is  inherent 
in  the  asbestos  proper.  Asbestos  felt,  saturated  with  bitumen,  is 
mostly  used  for  roofing,  and  is  ordinarily  applied  only  by  the  manu- 
facturer. Sheet  iron  covered  on  both  sides  with  asbestos  felt  is 
used  as  a  form  of  fireproof  and  waterproof  roofing. 

Asphalt.  Asphalt  is  a  solid  or  semi-solid  native*  bitumen  found 
in  a  natural  state,  or  produced  artificially,  as  petroleum  residuums. 
In  its  origin  it  is  decomposed  vegetable  matter  comprising  mainly 
carbon  and  hydrogen  of  complex  Ynolecular  construction,  but  also 
containing  oxygen,  sulphur  and  nitrogen  in  very  small  proportions. 
As  found  naturally,  asphalt  is  not  commercially  available  even 
after  the  impurities  are  removed,  being  usually  too  hard  and 
brittle  for  waterproofing  purposes.  This  is  ordinarily  remedied  by 
softening  or  fluxing  with  various  petroleum  oils,  which  fluxes  have  an 
important  effect  upon  the  finished  product.  The  fluxes  should  be 
sufficiently  stable  to  insure  against  too  rapid  hardening  of  the  fluxed 
asphalt.  To  avoid  the  process  of  fluxing,  which  requires  skill,  a 
straight  refined  asphalt  from  petroleum  oil  of  an  asphaltic  base  is 
used.  Pure  bitumen  has  a  density  less  than  water,  but  in  con- 
sequence of  impurities  mixed  with  it,  its  specific  gravity  varies  from 
1.0  to  1.7.  The  distinguishing  characteristics  of  all  bituminous 
substances  are  their  elasticity  and  binding  power  (or  adhesiveness), 
their  considerable  immunity  against  attack  by  water  and  their  solu- 
bility in  oils  and  certain  other  organic  compounds.  Most  water- 
proofing asphalts  are  elastic  at  ordinary  temperatures,  slightly 
viscid  at  low  temperatures  and  usually  liquid  at  comparatively  high 
temperatures.  Asphalt  is  quite  soluble  in  petrolic  ether,  and  entirely 
soluble  in  carbon  bisulphide.  Aside  from  the  paving  industry  where 
nearly  all  varieties  of  asphalt  are  used  and  the  varnish  industry 
where  the  very  best  and  purest  varieties  are  used,  it  is  chiefly  used  as  a 
saturant,  coating  and  bonding  material  for  felts  and  fabrics  in  the 
membrane  system  of  waterproofing,  and  as  binding  material  in  the 
mastic  system  of  waterproofing. 

Bakelite.  Bakelite  is  an  artificial  coal-tar  product  produced  by 
warming  together  equal  weights  of  phenol  and  formaldehyde  and  a 
small  amount  of  an  alkaline  agent.  The  resulting  mixture  separates 
into  two  layers,  the  lower  of  which,  when  heated  above  212  deg. 

*  The  term  "  native  bitumen  "  implies  that  the  natural  asphalt,  such  as 
Bermudez  or  Trinidad  asphalt,  requires  treatment  merely  for  the  removal  of 
water  and  extraneous  organic  and  inorganic  materials  before  using. 


WATERPROOFING   MATERIALS  155 

Fahr.  (100  deg.  Cent.)  and  worked  under  a  pressure  of  50  to  100 
pounds  per  square  inch,  results  in  a  hard,  solid,  inelastic  mass 
known  as  bakelite,  from  its  inventor,  Dr.  Leo  Baekeland.  This 
mass  has  a  specific  gravity  of  1.25  and  is  an  excellent  insulator, 
but  when  dissolved  in  neutral  petroleum  oil  is  used  as  a  varnish  for 
dampproofing  and  waterproofing  purposes. 

Benzine.  Benzine  is  a  light  volatile  petroleum  oil  used  as  a 
solvent  for  fats,  gums,  resin  and  bitumen.  Bituminous  solutions 
are  formed  with  this  petroleum  oil  and  used  as  a  surface  coating 
which  penetrates  into  the  pores  of  the  concrete  to  which  it  is  usually 
applied  with  a  brush.  After  evaporation  the  bitumen  remains 
in  the  pores  and  on  the  surface  in  the  form  of  a  thin  coat. 

Benzol.  Benzol  (or  benzene),  CeHe,  is  a  volatile,  colorless,  fluid 
hydrocarbon,  obtained  as  a  by-product  from  the  distillation  of  coal- 
tar  and  water-gas  tar,  and  from  petroleum.  It  was  discovered 
first  by  Faraday,  in  1825,  in  oil  gas,  and  by  Hofmann,  in  1845,  in 
coal-tar.  Benzol  is  an  active  solvent  for  fats,  resins,  most  bitumens 
and  is  used  for  that  purpose  in  waterproofing. 

Bituminous  Paints.  Some  bituminous  paints  are  made  of  solu- 
tions of  liquid  paraffin  in  either  asphalt  or  coal-tar  pitch,  or  by  mixing 
bitumen,  while  hot,  with  some  drying  oil  such  as  linseed  oil,  or  China 
wood  oil  with  either  of  which  the  bitumen  readily  enters  into  solution. 
Similar  products  are  obtained  by  mixing  paraffin  and  petroleum  with 
naphtha,  benzine  or  gasoline.  Some  of  these  paints  are  applied  hot, 
others  cold.  Some  will  adhere  to  a  wet  surface  or  a  surface  under 
water,  but  most  of  them  need  a  thoroughly  dry  surface.  They  are 
in  general  quite  durable,  cheap  and  easily  applied. 

Burlap.  Burlap  is  made  of  jute,  which  is  the  fiber  obtained  from 
the  inner  bark  of  the  Asiatic  plant,  genus  Corchorus,  of  the  Linden 
family.  It  is  a  very  cheap  fiber,  woody  in  its  nature  and  more 
perishable  than  flax.  It  is  mainly  grown  in  the  northeast  section 
of  India,  and  is  manufactured  in  Calcutta,  but  the  best  grades  of 
burlap  are  manufactured  in  Dundee,  where  the  industry  was  first 
started  on  a  commercial  scale  in  1838.  The  burlap  is  woven  in  many 
widths  and  has  considerable  tensile  strength.  It  is  sold  by  weight. 
The  most  used  varieties  for  waterproofing  purposes  are  7,  7|,  and  8 
ounces  per  square  yard.  This  weight,  however,  is  materially  affected 
by  the  moisture  content,  which  under  normal  conditions,  that  is, 
at  an  average  relative  humidity  of  70  per  cent,  the  jute  may  con- 
tain about  14  per  cent  of  moisture  by  weight.  Burlaps  of  these 
weights  have  open  meshes,  the  size  of  which  vary  with  the  weight, 
as,  for  example,  the  7-ounce  burlap  is  approximately  60  per  cent 


156  WATERPROOFING  ENGINEERING 

open,  the  mesh  being  about  i  inch  square.  The  size  of  the  mesh 
decreases  with  increase  of  weight.  Burlap  in  the  raw  state  is  some- 
times used  as  reinforcement,  in  the  membrane  system  of  water- 
proofing; but  when  saturated  and  coated  with  asphalt  or  oil-tar 
pitch,  which  preserves  it,  it  is  very  extensively  used  in  membrane 
waterproofing. 

Cast  Iron.  The  cast  iron  here  considered  is  that  usually  used  in 
the  construction  of  tunnels  and  for  tunnel  linings.  The  best  castings 
for  this  purpose  are  made  of  gray  iron  produced  by  the  cupola  proc- 
ess, of  the  second  melting.  The  castings,  called  tunnel  segments, 
must  be  true  to  pattern  and  flawless  in  every  other  respect.  In 
order  to  reduce  the  leakage  through  the  joints  to  a  minimum  the 
castings  are  faced  by  machine.  Provision  must  also  be  made  for 
calking  the  flanges  after  the  segments  are  erected  (see  Fig.  136) . 

Cement  Mortar  (Grout).  Cement  mortar  or  grout  is  a  mixture 
of  cement,  sand  and  water  in  any  proportion  from  1:1  to  1:6. 
This  mixture  is  termed  mortar  or  grout  when  the  size  of  sand  does 
not  exceed  that  Which  will  pass  100  per  cent  through  a  4-mesh  sieve, 
or  what  is  ordinarily  called  "  bird-sand."  When  it  does  exceed  the 
J-iflch  size,  a  smaller  aggregate  is  required  to  fill  the  voids  besides 
the  cement,  and  this  mixture  is  therefore  correctly  termed  con- 
crete. Cement  grout  of  the  proportion  1  :  1  or  1  :  2  is  used  very 
successfully  in  the  grouting  process  and  as  mortar  in  the  surface- 
coating  system  of  waterproofing.  In  the  above  proportions  it  is  very 
impervious,  but  as  a  coating  its  impermeability  also  depends  on  its 
thickness.  It  adheres  readily  to  a  roughened  surface  and  is  applica- 
ble to  any  kind  of  masonry. 

Clay.  Clay  is  an  uncrystallizable  silicate  of  aluminum.  It  is 
produced  in  nature  by  the  disintegration  of  the  various  silicates  of 
aluminum  in  the  stones  known  as  feldspars  and  micas,  due  to  weath- 
ering. Clays  are  usually  moist  or  wet  and  plastic  in  varying 
degrees  depending  in  part  on  the  fineness  of  the  grain  and  in  part 
on  the  amount  of  colloidal  substances  present.  This  plasticity  may 
be  increased  by  the  addition  of  water.  The  fineness  and  glue-like 
or  gelatinous  composition  of  clay  makes  it  a  good  inert  void  filler, 
and  in  small  quantities  is  used  for  that  purpose  in  mineral  paint  and 
mass  concrete.  It  is  often  used  as  a  cutoff  in  specially  constructed 
expansion  joints  in  masonry  structures.  In  the  form  of  a  thick 
blanket  (not  less  than  4  inches  thick)  applied  to  an  underground 
structure,  for  instance,  it  can  be  made  a  very  efficient  waterproofing 
medium  for  equal  mixture  of  clay  and  Portland  cement  is  used  for 
a  like  purpose. 


WATERPROOFING   MATERIALS  157 

Coal-tar  Pitch.  Coal-tar  pitch  is  a  semi-solid  or  solid  residue 
resulting  from  the  fractional  distillation  or  boiling  of  coal-tar.  This 
process  removes  certain  volatile  oils  and  results  in  a  black,  more  or 
less  viscid  residuum  product  called  coal-tar  pitch.  There  are  various 
grades  of  pitch,  the  best  being  used  for  general  waterproofing.  In 
comparison  with  asphalt,  this  best  grade  of  coal-tar  pitch  is  harder 
at  low  temperatures  and  more  liquid  at  high  temperatures  than 
the  asphalt.  It  is,  however,  more  adhesive  at  ordinary  temperatures 
and  less  affected  by  water  than  most  asphalts;  but  it  is  somewhat 
less  durable  in  air.*  Coal-tar  pitch  contains  free  carbon,  in  amounts 
depending  on  the  method  and  degree  of  reduction,  and  the  source 
of  the  tar.  The  more  free  carbon  in  pitch  up  to  about  30  per  cent 
the  less  it  is  affected  by  changes  in  temperature  and  apparently  has 
more  "  life  "  than  another  with  less  free  carbon,  f  Coal-tar  pitch  is 
extensively  used  as  a  saturant,  coating  and  bonding  material  for 
waterproofing  and  roofing  felts  and  fabrics  and  is  in  close  competition 
with  asphalt  for  use  as  binder  in  the  membrane  system  of  water- 
proofing. 

Cotton  Drill.  Cotton  drill,  as  usually  used  in  the  membrane 
system  of  waterproofing,  is  a  woven-cotton  fabric,  weighing  not  less 
than  4  ounces  to  the  square  yard.  This  weight  of  cotton  fabric 
has  a  thread  count  of  56  by  60  per  square  inch.  Different  grades 
are  made,  but  those  generally  used  vary  in  thread  count  between 
34  by  34  and  66  by  68,  per  square  inch,  both  inclusive.  When  either 
saturated,  or  saturated  and  coated  with  bitumen,  these  cotton 
fabrics  are  sold  as  standard  products,  but  often  also  under  various 
trade-names.  The  cheaper  grades  are  somewhat  less  durable,  and 
the  better  grades  are  usually  more  expensive  per  yard  than  most 
waterproofing  felts  or  jute  fabrics.  Treated  cotton  fabric,  in  com- 
parison with  the  untreated,  gains  about  20  per  cent  in  strength 
due  to  treatment.  It  is  comparatively  close-woven,  and  therefore, 
unlike  the  open-mesh  jute  fabric  which  acts  only  as  a  reinforcment 
in  the  bituminous  membrane,  it  acts  also  as  a  waterproofing  agent 
in  approximately  the  same  manner  that  waterproofing  felts  do,  that 
is,  it  helps  to  keep  the  water  out. 

Elaterite.  Elaterite  is  a  soft,  elastic  variety  of  asphalt  (hydro- 
carbon), resembling  India  rubber,  mined  in  Utah  and  Colorado, 
U.  S.  A.,  and  in  several  places  in  England,  notably  in  Derbyshire. 
It  is  subtranslucent,  has  a  brownish  color,  and  a  specific  gravity 
varying  from  0.9  to  1.0.  It  is  also  known  as  "  mineral  rubber." 

*  American  Society  for  Testing  Materials,  June  24,  1913. 
|  American  Railway  Engineers'  Association,  Vol.  14,  p.  844, 


158  WATERPROOFING  ENGINEERING 

Commercially  it  is  combined  with  certain  petroleum  oils,  linseed 
oil,  asphalt,  gilsonite,  and  even  castor  oil  (because  the  latter  is  a 
non-drying  oil),  and  used  as  a  surface  coat  on  concrete.  The  com- 
pounds thus  formed  are  quite  plastic  at  all  temperatures  to  which 
this  climate  is  subject  to.  Elaterite  is  very  difficult  to  melt,  but  in 
solution  with  various  materials  forms  a  much  used  dampproofing 
compound. 

Felt  (Waterproofing) .  Felt  made  for  waterproofing  purposes  is  a 
product  composed  chiefly  of  pulp  or  cotton  rags  with  a  little  wool; 
the  latter  makes  the  felt  open  and  spongy,  and  materially  increases 
its  saturating  power.  The  first  mechanical  process  for  making  felt 
was  invented  by  J.  R.  Williams,  an  American,  about  1820.  It  is 
made  in  sheet  form,  usually  36  inches  wide,  and  saturated  with  asphalt 
or  tar.  The  asphalt  felting  has  an  advantage  over  ordinary  coal-tar 
felting,  in  that  it  does  not  become  brittle  under  the  influence  of  heat 
or  with  age.  As  now  made  waterproofing  felt  comes  in  several 
thicknesses  and  is  sold  by  weight  or  roll,  the  standard  for  the  latter 
being  a  roll  containing  3  or  4  squares,  plus  8  to  12  square  feet  per 
square  extra  for  laps.  The  quality  of  the  raw  felt  is  designated  by 
a  number  as,  for  instance,  No.  23  felt  would  mean  a  felt  equal  in 
weight  to  a  ream  of  480  sheets  each  one  foot  square.  A  No.  28  felt 
would  be  one  weighing  28  pounds  per  ream.'  These  numbers  also 
happen  to  approximate  the  weight  of  the  felt  in  grams  per  square 
foot,  which  fact  it  may  be  useful  to  remember.  There  are  soft  and 
hard  felts  made,  hence  the  word  soft  or  hard  must  follow  each  number. 
The  soft  felts  are  usually  asphalt  treated,  the  hard  ones,  tar  treated. 
The  soft  felts  are  usually  dearer,  because  they  contain  more  wool. 
All-wool  felt  is  generally  not  made  because  of  its  high  cost,  softness 
and  tenderness.  A  wool  content  of  about  25  per  cent  produces  a 
felt  of  good  saturating  power,  and  saturation  is  very  essential  for 
the  preservation  of  all  the  raw  felts.  Good  saturated  felts  are  quite 
durable,  but  they  lack  tensile  strength,  though  they  gain  about  500 
per  cent  strength  due  to  such  treatment.  They  readily  absorb  water 
though,  in  spite  of  their  saturation. 

Gasoline.  Gasoline  is  one  of  the  very  volatile  distillates  of  petro- 
leum. It  consists  of  a  mixture  of  several  hydrocarbons  containing 
carbon  and  hydrogen  in  varying  percentages.  Its  chief  use  is  for 
fuel,  but  in  waterproofing  it  serves  as  the  distillate  or  "  carrier  " 
for  many  bitumens  which  readily  dissolve  therein.  These  solutions 
are  applied  cold  to  the  surface  of  masonry,  but  mainly  for  damp- 
proofing  purposes.  The  gasoline  penetrates  the  pores  of  the  masonry 
surface,  carrying  with  it  the  bitumen  which  remains  after  evapora- 


WATERPROOFING   MATERIALS  159 

tion.  Thus,  besides  forming  a  film  on  the  surface  the  pores  are  also 
barricaded. 

Gilscnite.  Gilsonite  is  a  hard  and  brittle,  native  bitumen,  mainly 
found  in  Colorado  and  Utah,  with  a  specific  gravity  of  1.07.  It  is 
lustrous  black  and  equally  soluble  in  cold  carbon  tetrachloride  and 
carbon  bisulphide.  It  is  also  readily  soluble  in  heavy  asphaltic 
petroleum.  When  mixed  or  fluxed,  while  hot,  with  certain  petroleum 
residuums  (it  begins  to  melt  at  about  480  deg.  Fahr. — 249  deg.  Cent.) 
in  proportions  according  to  the  consistency  desired,  a  rubbery  and 
somewhat  elastic  but  only  slightly  ductile  material  is  formed.  Gil- 
soriite  is  mainly  used  for  making  dampproof  paints  and  varnishes 
and  proprietary  waterproof  compounds  mostly  for  surface  coatings. 
It  is  sometimes  mixed  with  a  light  asphaltic  residue  to  bring  the 
latter's  consistency  up  to  certain  specification  requirements  for  par- 
ticular waterproofing  purposes. 

Grahamite.  Grahamite  or  "  Choctaw  "  is  a  hard  and  brittle 
native  bitumen  mainly  from  Oklahoma,  with  a  specific  gravity  of 
1.14.  The  deposit  is  now  exhausted.  It  is  a  dull  black  and  melts 
only  with  great  difficulty  (at  about  500  deg.  Fahr. — 260  deg.  Cent.) 
and  therefore  has  but  a  limited  use.  It  is  slightly  soluble  in  alcohol 
and  partly  so  in  ether,  petroleum,  and  benzol,  but  almost  completely 
in  turpentine  and  entirely  in  carbon  bisulphide  and  chloroform.  It 
is  used  for  the  same  purposes  as  gilsonite. 

Graphite.  Graphite  is  essentially  a  pure  carbon  which  comes  in 
two  forms — flake  and  amorphous — and  found  abundantly  in  nature. 
It  is  friable  and  has  an  oily  quality,  for  which  reason  it  acts  as  a 
lubricant.  (Lamp-black  or  soot  should  not  be  substituted  for 
graphite  because  they  have  not  the  same  properties.)  Graphite 
when  finely  ground  and  mixed  with  silica  and  linseed  oil  is  commonly 
used  as  a  preservative  paint  for  metals.  For  waterproofing  it  has  a 
limited  use  as  an  integral  because  of  the  black  color  it  gives  to  the 
concrete.  Hydrated  lime  serves  the  same  purpose,  i.e.,  as  a  lubricant 
for  the  concrete  aggregate,  without  this  defect.  Graphite  enters 
into  many  dampproofing  compounds. 

Gravel.  Gravel  is  an  aggregation  of  water-worn  and  rounded 
fragments  of  rocks,  in  which  quartz  is  the  most  common  mineral. 
Included  under  the  name  gravel  are  pebbles  ranging  in  size  from 
J  inch  to  2  inches.  Gravel  is  usually  classified  according  to  the 
largest  size  pebble  which  it  contains  as,  for  instance,  IJ-inch  gravel; 
1-inch  gravel;  f-inch  gravel,  etc.  For  making  impervious  concrete, 
gravel  must  be  sound  and  clean.  Concrete  is  considerably  densified 
by  using  gravel  graded  from  fine  to  coarse,  but  the  best  results  follow 


160 


WATERPROOFING  ENGINEERING 


when  it  contains  no  pebbles  that  will  pass  through  a  hole  f  inch  in 
diameter  and  none  that  will  not  pass  through  a  hole  l\  inches  in 
diameter.  No  gravel  that  is  all  of  one  size  or  practically  so  should 
be  used  where  impervious  concrete  is  desired. 

Jute  Fabric.  Jute  fabric*  employed  in  the  art  of  waterproofing 
is  a  burlap  saturated  and  coated  with  asphalt  or  coal-tar  pitch. 
When  thoroughly  saturated  and  coated  it  is  very  much  less  perishable 
than  raw  burlap,  while  its  strength  is  nearly  doubled  thereby.  It 


m  Hint  unit 


...in  utisti 

«!*&»•  *t«l*f|, 


1 » «•«•»«  » ' 

«||*t*«*i»   »   «*«*«*ll 

•«••*••••!«.  4  iifti*»*i 
•*l»»»«»lf  •»»»••»• 

tlfiPUWMlf  *!*!.• 


FIG.  62. 

^4.  Seven-ounce  Untreated  Burlap,  Showing  open  Mesh. 
B.  Same  Burlap,  Saturated  and  Coated  with  Asphalt. 

retains  between  35  and  50  per  cent  of  its  open  mesh  after  treatment, 
becomes  more  pliable,  and  weighs  between  14  and  18  pounds  per  100 
square  feet.  It  acts  as  a  reinforcement  in  the  waterproofing  mem- 
brane much  the  same  as  does  expanded  metal  in  reinforced  concrete 
slabs.  It  is  now  very  extensively  used  for  waterproofing  under- 
ground structures,  and  is  in  keen  competition  with  felt,  which, 
formerly,  was  used  exclusively.  Fig.  62,  A,  shows  a  photographic 
reproduction  of  a  piece  of  7-ounce  raw  burlap;  Fig.  62,  B,  shows 
the  same  piece  properly  saturated  and  coated  with  bitumen. 

*  "Manufacture,  Test  and  Use  of  Waterproofing  Fabric,"  Engineering  News, 
September  24,  1914. 


WATERPROOFING   MATERIALS  161 

Mastic.  Mastic  employed  in  the  art  of  waterproofing,  is  composed 
of  asphalt  or  coal-tar  pitch  mixed  with  cement  or  limestone  dust 
often  also  with  sand,  and  all  in  varying  proportions  depending 
on  the  particular  use  to  which  it  is  put.  Mastic  may  also  be  made 
of  fluxed  natural  rock  asphalt  and  grit.  The  mineral  matter  in  the 
mastic  gives  it  "  body  "  i.e.,  makes  it  more  substantial,  raises  its 
melting-point,  lessens  the  fluidity  and  increases  its  bearing  power 
as  compared  with  the  bitumen  used.  The  latter  properties  depend 
on  the  relative  proportion  of  the  bitumen  and  mineral  matter.  The 
usual  proportions  for  waterproofing-mastic  such  as  used  with  bricks 
to  form  a  brick-in-mast'ic  layer  are  from  30  to  50  per  cent  of  bitumen, 
the  remainder  being  equal  proportions  of  sand  and  cement.  The 
sand  used  in  making  the  mastic  is  usually  fine  enough  to  pass  100 
per  cent  through  a  10-mesh  sieve.  In  some  cases,  the  mastic  is 
used  as  mortar  with  bricks  for  waterproofing  floors,  walls,  roofs  and 
underground  structures.  It  is  often  used  alone  to  form  a  continu- 
ous sheet  an  inch  or  more  in  thickness,  to  waterproof  subsurface 
structures.  For  such  use  the  mastic  may  contain  from  10  to  15 
per  cent  of  bitumen,  8  per  cent  cement,  40  to  45  per  cent 
limestone  dust,  25  per  cent  grit  and  from  12  to  17  per  cent 
of  sand. 

Naphtha.  Naphtha  is  a  thin  white  oil  obtained  mainly  from 
petroleum  by  distillation  and  also  from  the  distillation  of  wood  and 
coal-tar.  There  are  several  varieties  and  grades  of  naphtha  and 
they  are  differentiated  by  their  boiling-points  and  specific  gravity 
but  all  are  hydrocarbons.  Commercial  bitumen  is  partly  soluble 
in  naphtha  but  when  heated  in  a  steam-jacketed  kettle  and  not 
thinned  out  too  much,  a  mixture  of  the  two  is  obtained  in  which  the 
part  of  the  asphalt  not  dissolved  is  held  in  suspension.  In  this  form 
it  is  used  for  making  bituminous  dampproofing  paints. 

Oil-tar  Pitch.  Oil-tar  pitch  is  the  residue  of  the  distillation  of 
oil  tar,  which  itself  is  a  by-product  of  the  manufacture  of  oil  gas 
or  carbureted  water  gas.  It  is  produced  in  the  cracking  of  oil  vapors 
at  very  high  temperatures.  This  process  causes  the  oils  to  undergo 
marked  changes  and  to  acquire  some  of  the  characteristics  found 
in  coal  tar.  These  oils  are  then  distilled  down  and  treated  much  as  is 
coal  tar,  resulting  in  what  is  known  as  oil-tar  pitch.  The  free  carbon 
content  of  oil-tar  pitch  is  low,  ranging  between  5  and  15  per  cent;  it 
is,  however,  always  less  viscid  than  coal-tar  pitch,  though  about  equal 
in  its  resistance  to  the  action  of  water  and  not  materially  less  stable 
than  coal-tar  pitch.  Its  chief  use  is  on  roofs  of  buildings  as  a  roof- 
ing binder  and  sometimes  as  a  saturant  for  waterproofing  felts  and 


162  WATERPROOFING  ENGINEERING 

fabrics.  Where  -coal-tar  pitch  is  to  be  applied  as  a  surface  coat, 
oil-tar  pitch  is  often  used  as  a  primer  because  of  its  penetrating 
power,  but  for  this  purpose  dead  oil  is  preferable. 

Paper.  Paper  was  first  made  by  the  Chinese,  from  whom  it  spread 
to  other  races,  and  was  brought  to  Europe  in  the  Twelfth  Century. 
The  first  paper  mill  in  America  was  built  by  William  Rittenhouse, 
at  Roxborough,  near  Philadelphia,  in  1690.  There  are  innumerable 
varieties  of  building  paper  on  the  market,  but  in  waterproofing 
only  two  or  three  of  these  are  used.  These  are  made  of  various 
kinds  of  wood  pulp,  rope,  rags  or  wool  or  from  a  combination  of  pulp 
and  rags  or  wool.  None  of  these  papers  can  be  completely  saturated 
with  bitumen,  but  all  can  be  sufficiently  saturated  to  preserve  them 
for  a  considerable  time.  Those  known  as  "  building  papers  "  are 
not  saturated  at  all.  Some  papers  are  merely  coated  on  one  or  both 
surfaces  with  bitumen.  Some  are  weak  in  tension,  others  very 
strong,  and  of  late  a  very  strong  variety  of  paper  has  been  success- 
fully treated  and  is  sometimes  used  in  place  of  felt. 

Paper  Burlap.  Paper  burlap,  as  made  for  waterproofing  pur- 
poses, is  an  open  mesh  paper  fabric,  similar  to  jute  burlap  and  some- 
times substituted  for  it.  It  can  be  saturated  with  bitumen  only 
with  difficulty.  It  may  be  used  in  waterproofing  in  the  same  manner 
as  jute  burlap.  It  comes  in  several  weights  and  widths  and  is 
slightly  reinforced  with  cotton,  but  it  is  not  nearly  so  strong  as  the 
jute  variety.  It  is  also  more  perishable.  By  pasting  a  very  thin 
tissue  paper  completely  over  one  side  of  the  paper  burlap  and  coat- 
ing the  whole  with  a  tacky  asphalt  or  coal-tar  product,  it  is  made 
into  an  efficient  electric  cable  duct  wrap. 

Paraffin  (Solid).  Solid  paraffin  is  a  hard,  white,  waxlike  sub- 
stance, chemically  of  the  higher  hydrocarbons.  It  is  obtained  by 
distillation  from  petroleum,*  but  is  also  found  native  in  coal  and 
other  bituminous  strata.  The  manufacture  of  paraffin  was  begun 
in  1851  by  James  Young,  a  Scottish  chemist.  It  is  very  inert,  insoluble 
in  water,  and  can  be  mixed  in  all  proportions  in  various  oils  when 
in  a  melted  condition  but  lacks  adhesiveness  and  is  useless  as  a 
binding  material.  For  waterproofing  it  is  often  mixed  with  asphalt 
(complete  solution  therein  is  essential) ,  or  used  alone  in  various  ways, 
e.g.,  to  render  fabrics  waterproof.  When  used  unblended,  as  a 
masonry  surface  coating  it  is  the  most  efficient  waterproofing  medium 
for  the  purpose.  It  is  also  used  in  the  manufacture  of  secret  (?) 
waterproofing  compounds. 

*  The  Pennsylvania  and,  in  general,  the  Eastern  (U.  S.  A  )  oils  are  largely 
made  up  of  compounds  of  the  paraff  n  scries. 


WATERPROOFING   MATERIALS 


163 


Paraffin  Oil.  Paraffin  oil  is  a  by-product  of  the  manufacture  of 
paraffin.  It  is  a  liquid  compound  practically  of  the  same  nature  as 
the  solid  paraffin  with  the  same  properties  and  adaptability  as 
regards  waterproofing.  Both  kinds  of  paraffin  are  extensively 
used  as  surface  coatings  for  stone,  brick,  and  concrete,  making  the 
latter  both  dampproof  and  waterproof.  Stones  are  often  impreg- 
nated with  paraffin  to  prevent  erosion  when  exposed  to  the  elements. 

Sand.  Nearly  all  sand  is  more  or  less  pure  quartz  grains  which 
will  all  pass  through  a  J-inch  sieve  with  not  more  than  8  per  cent 
passing  a  No.  100  sieve.  The  sand  best  suited  for  making  impervious 
concrete  is  coarse,  sharp  and  silicious,  containing  not  more  than  2 
per  cent  of  mica,  loam,  dirt  or  clay,  separately  or  combined.  For 
good  results  as  regards  impermeability  it  should  be  graded  about  as 
follows : 


No.  of  Sieve. 

Limit  of 
Fineness 
(Per  Cent 
Passing)  . 

Limit  of 
Coarseness 
(Per  Cent 
Passing)  . 

4 

100 

95 

8 

95 

85 

16 

75 

40 

30 

50 

20 

50 

30 

2 

100 

6 

0 

See  Appendix  1  for  explanation  of  mechanical  analysis  curves 
for  grading  concrete  aggregates. 

Steel  Plate.  Steel  plate  used  for  tunnel  linings  is  made  by  the 
open-hearth  process.*  In  tunnel  construction,  it  often  acts  both  as  a 
structural  component  of  the  tunnel  and  its  waterproof  lining.  To 
reduce  leakage  through  the  joints  to  a  minimum  after  erection,  the 
plates  should  be  perfectly  fitted  and  riveted  through  properly 
reamed  holes.  Edges  of  all  plates  must  be  planed  and  calked  inside 
and  out.  When  steel  plates  are  used  for  tanks  and  sometimes  even 
for  structural  purposes  it  is  also  necessary  to  make  the  joints  water- 
tight. A  very  good  scheme  is  to  introduce  a  strip  of  treated  felt 
a  little  wider  than  the  pitch  of  rivets  between  the  joints.  The  heat 
and  compression  of  the  rivets  bring  out  the  cementing  properties 
of  the  joint  filler. 

Stone  Aggregate.  Stone  used  for  concrete  consists  mainly  of 
trap,  limestone,  marble,  granite,  syenite  and  gneiss.  The  composi- 

*  The  Journal  of  the  Municipal  Engineers  of  the  City  of  New  York,  Vol.  1, 
No.  6,  p.  16;  December  1,  1915. 


164  WATERPROOFING  ENGINEERING 

tion  and  characteristics  of  these  stones  are  more  or  less  a  matter  of 
common  knowledge,  and  a  discussion  of  their  properties  would 
encumber  this  article.  What  is  true  of  gravel,  as  regards  the  making 
of  dense  concrete,  is  approximately  true  of  any  of  these  stones  for 
the  same  use.  See  Appendix  1  for  explanation  of  mechanical  analysis 
curves  for  grading  concrete  aggregates. 

Tar.  (A)  Coal  tar:  Coal  tar  is  a  black,  more  or  less  viscid, 
oily  liquid,  a  mixture  of  hydrocarbon  distillates  resulting  from  the 
destructive  distillation  of  soft  coal  in  the  production  of  illuminating 
gas.  It  was  first  recovered  in  1771  by  Stauf,  a  German  chemist. 
There  are  various  kinds  of  tars,  depending  on  the  type  of  oven  and 
kind  of  coal  used.  The  chief  difference  in  these  tars  is  the  varying 
percentage  of  free  carbon  present.  By  fractional  distillation,  that  is, 
by  the  removal  of  certain  of  the  more  volatile  oils  present  in  the  crude 
tar,  it  can  be  carried  to  a  point  at  which  the  residuum  in  the  still 
has  acquired  any  desired  consistency  at  normal  temperature.  This 
semi-solid  or  solid  residual  product  is  called  pitch.  The  best  water- 
proofing pitches  are  obtained  from  straight-run  (unadulterated) 
coal  tar  produced  at  reasonably  high  temperatures,  though  for 
roofing  purposes  pitch  is  also  made  of  oil  and  'water-gas  tars.  Coal 
tar  is  used  as  a  dampproof  and  protective  paint  and  for  saturating 
waterproofing  felts. 

(B)  Water-gas  tar:  Water-gas  tar  is  a  mixture  of  hydrocarbon 
distillates,  produced  by  cracking  oil  vapors  at  high  temperatures 
in  the  manufacture  of  carbureted  water  gas.  Crude  water-gas  tar 
is  a  thin,  oily  liquid  having  a  specific  gravity  lying  usually  between 
1  and  1.10.  As  a  rule  it  contains  a  considerable  quantity  of  water, 
which  is,  however,  largely  removed  by  mechanical  devices  before 
the  tar  is  placed  upon  the  market.  The  composition  of  water-gas 
tar  varies  with  the  character  of  the  oil  which  is  carbureted  and 
varying  conditions  affecting  the  process.  It  always  shows  a  low 
percentage  of  free  carbon,  usually  less  than  2  per  cent,  and  is  more 
easily  decomposed  and  more  affected  by  water  than  coal  tar.  In 
crude  form  it  is  used  as  a  road  dust-palliative.  When  reduced  to  the 
proper  consistency  by  distillation  it  is  used  as  a  road  binder,  in  the 
manufacture  of  a  few  minor  waterproofing  materials  and  for  treating 
a  special  grade  of  waterproofing  felt  and  fabric. 

Water.  The  term  "  water  "  is  ordinarily  understood  to  mean  the 
liquid  composed  of  two  parts  of  hydrogen  and  one  part  of  oxygen, 
chemically  combined.  But  to  the  engineer  the  "  EkO  "  of  the  water 
is  of  less  concern  than  the  suspended  and  dissolved  matter  in  the  water 
in  general  use.  Its  abundance  is  too  often  taken  as  proof  positive 


WATERPROOFING   MATERIALS  165 

of  its  purity.  But  reasonably  pure,  clean,  fresh  water  is  not  always 
available.  Still  these  qualities  and  the  amount  used  in  making  a 
specific  mixture  of  concrete  are  as  essential  in  the  making  of  good 
concrete  as  good  cement,  sand  and  stone.  Water  for  good  concrete 
should  be  free  of  every  form  of  pollution,  excessive  amounts  of  acids 
and  alkalies  and  all  forms  of  organic  matter.  Salt  water  should 
never  be  used  in  making  reinforced  concrete.  The  presence  of  any 
of  these  foreign  ingredients  affects  the  cement  more  or  less  and 
reduces  the  density  and  consequently  the  impermeability  of  the 
concrete.  The  functions  of  water  in  concrete  are:  (a)  to  form,  with 
the  cement,  the  binding  material  uniting  the  sand  and  stone;  this  is 
accomplished  automatically  by  dissolving  the  cement,  forming  acids 
from  anhydrides,  and  bringing  these  new  acids  and  dissolved  bases  of 
cement  into  intimate  contact  for  chemical  reaction;  (b)  to  flux  the 
cementing  substances  over  the  surfaces  of  the  aggregate  so  as  to 
insure  extensive  adhesion;  (c)  to  act  as  a  lubricant  for  the  aggregate. 
These  are  completely  operative  only  if  the  water  is  reasonably  pure. 

Some  of  the  materials  above  considered  are,  of  course,  used  for 
many  other  purposes  than  waterproofing,  but  such  enumeration 
would  be  foreign  to  this  subject. 

The  many  secret  compounds  referred  to  throughout  the  book 
consist  mostly  of  (a)  chemical  salts  and  limes;  (b)  solutions  of 
various  petroleums  and  linseed  oil,  and  (c)  mixtures  of  powdered 
metal,  slag  and  Portland  cement. 

Analyses  of  many  patented  waterproofing  materials  by  Govern- 
ment and  private  chemists  prove  some  of  them  of  questionable  merit, 
and  some  of  but  temporary  value,  imparting  impermeability  to 
concrete  but  for  a  short  time  only,  and  with  some  of  these  compounds 
unfortunately,  their  secrecy  more  often  overbalances  their  efficacy. 


CHAPTER  VI 
WATERPROOFING  IMPLEMENTS  AND   MACHINERY 

Applicability  of  Tools  and  Machinery  for  Waterproofing.  The 
tools,  implements  and  machinery  employed  in  the  waterproofing 
industry  are  somewhat  connected  with  the  asphalt  pavement  in- 
dustry with  which  most  engineers  and  contractors  are  more  or  less 
familiar.  Some  tools  are  used  in  common  and  some  implements 
are  easily  modified  to  suit  either  industry.  The  tools  and  implements 
are  usually  of  simple  construction,  and  some  are  often  home-made, 


Saturath  f  Tank 


Brush  to  Remove 
ricess  Bawdust 


FIG.   63. — Diagrammatic   View   Showing   Process   of  Saturating  and  Coating 
Burlap  or  Cotton  Fabric  with  Bitumen. 

though  all  are  supplied  by  manufacturers  who  make  a  specialty  of 
this  trade;  but  the  machinery,  such  as  is  used  for  saturating  and 
treating  waterproofing  felts  and  fabrics,  is  more  complicated  (see 
Fig.  63),  and  requires  design.  The  manipulation  of  most  of  these 
tools  and  machines,  however,  is  simple  and  does  not  require  partic- 
ularly skilled  labor,  either  in  the  field  or  factory.  There  are  varia- 
tions and  even  distinctly  different  forms  of  these  articles  in  the 
market,  but  those  described  herein  are  mostly  standard  or  fast 
becoming  so. 

VARIETIES  OF  MASTIC  MIXERS 

Spherical  Mastic-mixing  Kettle.  The  mastic-mixing  kettle 
shown  in  Fig.  64  is  very  extensively  used  by  general  waterproofers. 
The  pot  in  the  figure  fits  into  the  jacket,  or  mantle.  The  kettle 
and  mantle  are  made  of  steel  plate,  with  top  and  bottom  bands. 

166 


WATERPROOFING  IMPLEMENTS  AND  MACHINERY      167 


-   FIG.  64. — Asphalt  or  Mastic  Heating  Kettle. 


_ 


FIG.  65.— Typical  Dipper  and  Pouring  Pail  Used  in  Waterproofing  with  Asphalt 

or  Tar. 


168  WATERPROOFING  ENGINEERING 

The  bottom  of  the  kettle  is  riveted  but  easily  removable  when  burnt 
and  removal  is  necessary.  The  dimensions  of  the  kettle  are  as 
follows:  Kettle,  38  inches  diameter  at  top,  j^-inch  plate,  21  inches 
deep;  bottom,  f  inch  thick.  Mantle,  40  inches  diameter,  36  inches 
high,  of  3^-inch  plate.  Kettles  of  50  gallons  capacity  are  the  most 
generally  used.  Through  the  opening  in  the  mantle  a  wood  fire 
is  built  under  the  kettle  in  which  the  bitumen  gradually  melts. 
While  in  a  hot  and  molten  condition,  the  bitumen  is  poured  into 
small  kettles  or  pouring  pails  by  means  of  dippers,  both  of  which 
are  shown  in  Fig.  65. 

Cylindrical    Mastic-mixing    Kettle.     Cylindrical    mastic-mixing 
kettles  are  well  adapted  for  making  mastic  because  every  part  of 


FIG.  66.— Cylindrical  Mastic  Kettle. 

its  interior  surface  is  accessible  to  the  kettleman.  This  is  all  the 
more  so  because  straight-edged  stirrers  are  the  most  generally  used, 
regardless  of  the  type  of  kettle.  This  type  of  kettle  is  made  in  several 
sizes,  of  f-inch  metal,  with  sand  and  gravel-drying  pockets  on  either 
side  and  a  fire  space  underneath  the  cylinder,  as  shown  in  Fig.  66. 
The  kettle  rests  directly  on  the  ground  and  can  readily  be  carried 
away  by  four  men. 

Mechanical  Mastic  Mixer.*  The  mechanical  mixer  shown  in 
Fig.  67  is  constructed  so  that  it  can  be  drawn  without  any  difficulty 
to  any  location  or  to  any  part  of  the  work.  It  consists  of  a  steel 
rotary  drum  which  revolves  in  a  fire  brick-lined  steel  casing  set  on  a 

*  Originated  by  the  Guelich  Paving  Process  Co.  of  Philadelphia,  Pa.,  and 
patented  November,  1911. 


WATERPROOFING   IMPLEMENTS  AND   MACHINERY        169 

rectangular  I-beam  truck;  the  drum  proper  is  5  feet  long  and  34 
inches  in  diameter.  The  drum  heads  revolve  about  a  horizontal 
axis,  while  the  barrel  of  the  drum  has  a  6-inch  eccentricity  on  each 


FIG.   67. — Mechanical   Mastic    Mixer,    Rear   View.     (Patented   in   U.    S.    A., 

November,  1911.) 

end.  The  drum  is  perfectly  smooth,  being  butt  jointed.  Within 
the  drum  is  a  series  of  flat,  rectangular  paddles  set  at  an  angle  of 
45  degrees  with  the  axis.  Attached  to  the  forward  end  of  the  drum 


170  WATERPROOFING  ENGINEERING 

is  a  curved  rack  which  meshes  with  a  gear  driven  by  a  direct-connected 
gasoline  engine  also  at  this  end.  To  the  engine  is  connected  an  air 
blower  which  supplies  the  air  for  vaporizing  the  fuel  oil,  the  heat 
source  for  this  machine.  A  fire  box  is  connected  to,  but  underneath, 
the  truck  and  is  also  lined  with  fire  brick.  The  flame  spreads  on 
either  side  of  the  drum  and  comes  in  direct  contact  with  it.  For 
this  reason  the  torch  is  never  lighted  except  when  the  drum  is 
revolving. 

In  the  center  of  the  forward  head  of  the  drum  is  a  10-inch  hole 
through  which,  by  the  aid  of  a  hopper  the  machine  is  charged  while 
revolving.  The  rear  end  of  the  drum  is  used  for  discharging;  an 
opening  near  the  edge  of  the  drum  head,  provided  with  a  hinged  door, 
8  by  12  inches,  being  used  for  this  purpose.  In  this  hinged  door  is 
a  small  shuttle  door  through  which  the  material  in  the  drum  is 
sampled  while  being  cooked. 

In  starting  the  machine  the  mastic  constituents,  that  is,  the 
sand,  grit,  limestone  dust  and  cement,  are  thrown  into  the  drum 
through  the  hopper  and  at  the  same  time  pieces  of  asphalt  are  also 
thrown  in  so  as  to  mix  more  thoroughly  with  the  aggregate.  All 
materials  must  be  weighed,  but  none  of  them  needs  preheating 
preparatory  to  mixing. 

The  total  weight  of  the  machine,  when  empty,  is  about  3  tons. 
Its  dimensions  are:  height,  about  5  feet;  width,  4  feet;  and  length, 
8  feet. 

The  capacity  of  the  machine  is  about  1000  pounds  of  mastic  in 
about  thirty-five  minutes.  It  requires  one  engine  runner  and  two 
laborers  to  tend  this  machine,  and  between  1000  and  1400  square 
feet  of  1-inch  floor  mastic  or  sheet  mastic  for  waterproofing  purposes 
can  be  produced  by  it  per  working  day. 

The  drum  must  be  cleaned  after  each  day's  work.  This  is  accom- 
plished by  throwing  some  grit  into  it,  allowing  it  to  revolve  for  a 
few  minutes  while  the  torch  is  burning,  and  drawing  off  the  product 
gradually  until  the  drum  is  empty. 

VARIETIES  OF  HEATING  KETTLES 

Steam- jacketed  Heating  and  Mixing  Kettle.  Steam-jacketed 
kettles  for  heating  bituminous  materials,  or  mixing  bituminous 
mastic,  are  used  in  many  asphalt  plants  throughout  the  country; 
but  these  are  invariably  of  very  large  sizes,  ranging  between  200 
and  500  gallons  capacity,  and  also  of  various  forms. 

Small  kettles  of  this  type,  say  between  50  and  100  gallons  capa- 


WATERPROOFING  IMPLEMENTS  AND   MACHINERY        171 

city,  could  be  employed  on  engineering  work  where  large  quantities 
of  these  materials  are  used  for  floor  paving  or  waterproofing  purposes. 
While  this  has  never  been  tried,  so  far  as  the  author  is  aware,  never- 
theless he  feels  confident  that  it  would  result  in  marked  economy 
were  these  kettles  substituted,  where  possible  for  the  fire-heated 
kettles  of  the  present  day.  This  would  follow  for  several  reasons. 
It  is  a  demonstrated  fact  that  coal-tar  pitch  is  robbed  of  some  of  its 
volatile  oils  by  being  heated  over  a  fire  preparatory  to  its  use,  because 
of  the  concentration  of  heat  and  the  natural  lightness  of  some  of  the 
constituent  oils.  Asphalt  likewise  suffers  deterioration,  though  not  as 
readily  as  pitch.  The  cost  of  handling  fire-wood,  plus  the  cost  of  at 


Inner  Kettle 


FIG.  68. — Double-jacketed,  Steam-heated  Mastic  Mixing  and  Asphalt  Heating 

Kettle. 

A.  Kettle  with  mastic  mixing  device. 

B.  Pip?  connection  for  kettle. 

C.  Asphalt  heating  kettle,  showing  arrangement  of  jackets 

least  three  hours'  overtime  every  day  for  a  man  to  start  the  fires  under 
the  kettles  at  early  dawn;  the  lack  of  a  uniform  product  so  often  the 
result  of  making  hand-mixed  mastic;  the  fact  that  all  work  of  any 
magnitude  at  all,  has  a  steam  plant  working  practically  all  the  time 
with  considerable  waste  of  steam  for  lack  of  use ;  all  these  facts  taken 
together  and  the  frequent  need  for  replacing  the  burnt  fire-heated 
kettles  make  a  cost  item  to  be  considered  in  comparison,  and  would 
show  it  to  be  decidedly  advantageous  and  economical  to  use  the  steam- 
jacketed  kettles. 

Various  types  of  steam-jacketed  kettles  are  on  the  market  and 
used  for  various  purposes  such  as  making  chemicals,  paper,  glues, 
etc.  The  type  suitable  for  heating  bitumen  is  shown  in  Fig.  68,  C. 
This  is  made  of  plain  iron  with  or  without  a  cover  and  with  or  without 


172 


WATERPROOFING  ENGINEERING 


an  outlet  from  the  inner  kettle.  The  cost  of  this  kettle  depends  on 
\he  capacity:  45  gallons  costing  about  $66.00;  65  gallons  $81.00; 
100  gallons  about  $121.00.  Fig.  68,  A,  shows  the  kettle  adapted  to 
making  mastic  mechanically  by  the  addition  of  a  double  mixer,  gear, 
shaft  and  hand  crank  hinged  arbor.  The  cost  of  this  type  of  mixer 
also  depends  on  the  capacity,  namely,  45  gallons  about  $125.00; 
65  gallons  about  $150.00  and  1000  gallons  about  $207.00.  At  B  is 
shown  the  pipe  connections  for  each  style  of  kettle. 

The  steam  pressure  required  for  raising  the  cold  materials  in  these 
kettles  to  their  proper  temperature  is  about  100  pounds  per  square 
inch  applied  for  about  one  hour. 


FIG.  69. — Roofer's  Kettle,  Used  for  Heating  Bitumen  and  Mastic. 
A.   Mantle.          B.  Kettle. 

A  modified  steam-jacketed  kettle  can  be  made  out  of  the  present 
fire-heated  kettles  by  lining  them  with  steam  coils  suspended  from  the 
edges.  „ 

Round  Roofer's  Kettle.  The  kettle  shown  in  Fig.  69  is  used 
mostly  by  roofers  in  exactly  the  same  manner  as  the  asphalt  and  heat- 
ing mastic  kettles.  This  kettle  is  strongly  constructed,  handy 
for  small  jobs  and  for  patching  purposes.  These  roofer's  kettles 
are  generally  built  and  used  in  sizes  of  20,  30  and  50  gallons  capacity. 

Rectangular  Roofer's  Kettle.  The  roofer's  kettle  shown  in  Fig. 
70  is  made  rectangular  in  form  and  in  capacities  of  50,  100  and  150 
gallons.  They  are  built  of  No.  14  sheet  steel,  riveted  and  braced 
in  all  corners  with  angle  iron.  The  tank  is  made  with  bottom  semi- 
cylindrical  in  form,  separate  from  fire  box,  thus  facilitating  repairs 
in  replacing  burnt  bottoms.  The  furnace  is  reinforced  on  the  inside 


WATERPROOFING   IMPLEMENTS  AND   MACHINERY        173 

by  an  extra  thickness  of  No.  14  steel  to  resist  the  heat.  The  kettles 
are  usually  provided  with  four  carrying  handles  attached  to  the  side 
sheets  as  shown. 

Portable  Heating  Kettle  (Drag  Type).  In  Fig.  71  is  shown  a 
large  portable  heating  kettle  mainly  used  by  roofers.  It  is  very 
serviceable,  especially  the  davit,  which  greatly  facilitates  handling 
barrels.  In  warm  weather  the  heat  from  the  melted  bitumen  in 
the  kettle  is  sufficient  to  make  the  bitumen  flow  from  the  bung  of  the 
barrel,  which  is  placed  so  that  it  opens  downward.  This  keeps  the 
barrel  intact  which  may  then  be  used  again.  The  kettle  may  be  had 
in  capacities  of  150  to  500  gallons. 

Portable  Heating  Kettle  (Wagon  Type).  The  portable  heater 
shown  in  Fig  72  is  used  chiefly  by  roofers.  This  type  of  heater  is 


FIG.  70. — Stationary  Roofer's  Kettle.     (End  View  has  Outside  Jacket  Removed.) 


intended  for  long  hauls  and  small  jobs.  The  bitumen  can  be  heated 
while  being  hauled  to  the  work.  In  places  where  the  municipal 
authorities  will  not  allow  a  thoroughfare  to  be  blockaded  by  station- 
ary kettles,  this  is  found  a  desirable  outfit.  The  space  back  of  the 
driver's  seat  is  arranged  for  holding  wood,  having  sufficient  space 
for  about  two  days'  supply.  There  is  also  a  rack  for  carrying  pails, 
dippers,  mops,  etc.  The  heating  tank  is  provided  with  a  hinged 
cover.  This  type  of  heater  usually  comes  in  sizes  of  100  to  150 
gallons  capacity. 

Portable  Heating  Kettle  (Hand  Cart  Type).  The  portable  kettle 
illustrated  in  Fig.  73  is  much  used  by  roofers  and  waterproofers, 
particularly  the  latter,  because  it  is  made  in  as  small  capacities  as 
desired.  By  the  use  of  this  type  of  small  portable  heating  kettles, 
the  stationary  mixing  kettles  can  be  almost  any  distance  from  the 


174 


WATERPROOFING   ENGINEERING 


work,  and  the  bitumen,  or  mastic,  can,  by  means  of  them,  be  trans- 
ported hot  from  the  heating  or  mixing  kettles  to  the  place  of  applica- 
tion. The  smaller  portable  kettles  need  no  projecting  chimneys. 


FIG.  71. — Portable  Asphalt  and  Tar-heating  Kettle  with  Davit  Attachment. 

The  furnace  is  equipped  with  sheet  steel  bottom,  of  No.  12  gauge, 
and  is  tongue-riveted  to  the  tank.  It  has  a  wrought-iron  handle 
provided  with  a  foot  rest  in  front,  and  a  discharge  pipe  from  the  tank 
in  the  rear, 


WATERPROOFING   IMPLEMENTS   AND   MACHINERY        175 

Combination  Tar  and  Gravel  Heater.     A  tar  and  gravel  heater, 
similar  in   construction  to  but  usually  larger  than  the  portable 


FIG.  72.— Wagon  Type  of  Tar  and  Asphalt  Heater. 

kettle  shown  in  Fig.  73  is  used  by  roofers  and  general  waterproofers 
alike.     On  top  of  the  heater  are  two  doors,  one  enclosing  a  round- 


FIG.  73. — Hand-portable  Type  of  Tar,  Asphalt,  and  Mastic-heating  Kettle. 

bottom  tank  in  which  the  bitumen  is  heated,  and  the  other  an  inclined 
container  for  the  sand  or  gravel  which  is  drawn  out  as  needed  from  an 


176  WATERPROOFING  ENGINEERING 

upper  door  in  the  end.  A  lower  door  encloses  the  fire  box.  In  the 
rear  of  the  heater  is  a  spout  for  drawing  the  bitumen.  The  heater 
can  be  transported  from  place  to  place  by  attaching  it  to  a  wagon. 
The  standard  kettle  has  a  capacity  of  70  gallons  of  bitumen  and 
gravel.  This  heater  will  produce  one  ton  of  hot,  dry  gravel  per  hour. 

SUNDRY  WATERPROOFING  IMPLEMENTS 

Roofing  Mops.     The  mops  shown  in  Fig.  74  are  used  for  roofing 
and  waterproofing  alike.     They  are  made  of  a  cotton  warp,  attached 


FIG.  74. — Roofing  and  Waterproofing  Mops. 

to  wooden  handles  4  feet  long,  the  weight  and  length  of  warp  being 
as  follows : 

3-ounce  cotton  warp,    5J  inches  long. 

12-ounce  cotton  warp,    9J  inches  long. 

20-ounce  cotton  warp,  12    inches  long. 

32-ounce  cotton  warp,  15    inches  long. 

The  two  smallest  are  used  chiefly  for  roofing,  the  two  longest, 
chiefly  for  general  waterproofing. 

The  general  practice  is  to  buy  bales  of  cotton  warp,  and  make  the 
mops  on  the  work,  as  needed. 


WATERPROOFING  IMPLEMENTS  AND  MACHINERY       177 

Mastic  Stirrers.  Fig.  75,  A,  illustrates  an  efficient  type  of  mastic 
stirrer.  for  round-bottom  kettles.  Other  types  consist  of  a  long- 
handled  paddle  whose  end  is  shaped  like  an  oar;  or  an  iron  rod 
terminating  in  a  flat  triangle  as  shown  in  Fig.  75,  B.  This  is  best 
suited  to  the  cylindrical  type  of  mixing  kettle.  Another  type  of 
stirrer  is  made  of  a  coffin-shaped  piece  of  sheet  iron  perforated  with 
1-inch  holes,  and  securely  fastened  to  the  end  of  a  long  pole.  Some- 
times a  strong  flat  stick,  picked  up  on  the  work,  is  used.  This  type, 
however,  as  well  as  the  oar  or  coffin-shaped  stirrers,  are  not  efficient 
tools.  A  modification  of  the  stirrer  shown  in  Fig.  75,  A,  consists  in 
making  the  frame  square,  but  as  the  majority  of  kettles  used  are 
round-bottomed,  this  also  does  not  make  an  efficient  stirrer.  In  the 
stirrer  shown  in  the  figure  the  handle  is  made  of  wood  inserted 
into  an  iron  rod,  which  terminates  in  a  ring,  the  hole  of  which  is 


FIG.  75. 

A.  Paddle  Type  of  Mastic  Stirrer,  (Hnch  Wire  Mesh). 

B.  Stirring  Rod. 


occupied  by  a  f-  or  |-inch  iron- wire  screen  of  J-inch  mesh  securely 
fastened  to  the  ring. 

Dipper  and  Pouring  Pail.  The  dipper  and  pouring  pail  shown  in 
Fig.  65  are  usually  made  of  galvanized  sheet  iron,  or  other  sheet 
metal,  in  several  sizes  and  capacities,  the  most  common  of  which 
being  the  3-gallon  type.  They  are  both  reinforced  with  a  heavy 
wire  band  at  the  top.  The  base  of  the  ferrule  of  the  best  dippers  is 
riveted  to  the  bottom.  The  dippers  have  wooden  handles  from 
6  to  8  feet  long.  The  type  of  pouring  pail  shown  in  Fig.  76,  A,  may 
serve  also  as  a  melting  pot  and  when  so  used,  is  placed  in  a  suitable 
portable  furnace,  like  a  salamander.  The  seams  in  this  kettle  are 
rolled  and  the  top  is  divided  and  hinged  across  the  middle. 

Asphalt  Smoother.  The  asphalt  smoothers  shown  in  Fig.  76,  B, 
have  but  a  limited  use  in  waterproofing  work.  They  are,  however, 
very  efficient  for  the  limited  purpose  for  which  they  are  applicable, 


178 


WATERPROOFING  ENGINEERING 


especially  the  very  small  ones,  whose  base  is  about  3  by  4  inches 
(curved  like  the  larger  smoothers)  with  short  iron  handles.  They 
are  heated  and  used  to  soften  the  exposed  ends  and  laps  of  bituminous 
membranes  to  insure  a  good  waterproof  joint  between  old  and  new 


work.  The  manner  of  using  the  smoother  for  waterproofing  is  the 
same  as  in  paving  work.  The  larger  smoothers  are  made  of  cast 
iron  in  two  sizes,  their  faces  being  ground  smooth  and  to  a  curve. 
They  are  provided  with  handles  made  of  IJ-inch  pipe,  bent  at  the 
upper  end,  and  welded  to  a  steel  stub  cast  in  the  head  of  the  smoother. 


WATERPROOFING  IMPLEMENTS  AND   MACHINERY       179 

Gasoline  Torch.  The  torch  shown  in  Fig.  76,  D,  is  the  one  most 
generally  used  for  heating  laps  and  small  surfaces  of  old  waterproofing 
of  the  membrane  and  surface  coating  types.  It  is  sometimes  also 
used  for  heating  concrete  in  the  mixer,  in  freezing  weather,  where  it 
is  very  effective,  and  helpful  in  producing  good  concrete  in  cold 
weather.  This  torch  produces  a  blue  flame  of  great  heat  efficiency. 
The  shipping  weight  of  this  type  of  torch  is  about  4|  pounds. 


FIG.  77.— Method  of  Drying  and  Sieving  Sand;  Typical  Arrangement  of  Fire- 
heated  Kettles  for  Making  Mastic.  (Note  Yoke  for  Carrying  Pails  of 
Hot  Pitch  or  Mastic.) 

Asphalt  Cutter.  In  Fig.  76,  C,  is  shown  an  asphalt  cutter  widely 
used  where  asphalt  or  hard  tar  products  are  employed  in  construction. 
With  it,  wooden  barrels  and  tin  drums,  in  both  of  which  the  pitch 
and  asphalt  are  received  on  the  work,  are  readily  cut  up,  exposing 
the  materials.  These  are  in  turn  cut  up  into  small  pieces  for  easy 
handling.  The  cutters  are  made  of  tool  steel,  with  tempered  edges, 
thus  giving  long  service  before  the  tool  has  to  be  repaired.  The 
length  of  cutter  from  edge  to  edge  is  20J  inches;  width  of  edge  3 
inches;  shipping  weight  of  double-edge  cutter  is  10  pounds. 


180 


WATERPROOFING  ENGINEERING 


Gravel  Heating  Pan.  The  gravel  heating  pan  shown  in  Fig. 
76,  E,  is  much  used  by  roofers  and  general  waterproofers.  In  ser- 
vice it  is  usually  supported  by  several  bricks  under  each  corner 


FIG.  78.— Method  of  Drying,  Heating,  and  Sieving  Sand  in  Large  Quantities. 


permitting  a  wood  fire  to  be  built  underneath.  The  sand  or  gravel 
is  spread  over  the  pan,  and  dried  or  heated  as  desired.  These  pans 
are  made  of  soft  steel  with  riveted  sides.  The  most  generally  used 
size  is  106  inches  long,  42  inches  wide  and  8  inches  deep. 


WATERPROOFING  IMPLEMENTS  AND  MACHINERY        181 


Sand  and  Gravel  Heating  Pipe.  The  pipes  shown  lying  on  the 
ground  in  Fig.  77  are  sheet  metal,  but  more  usually  old,  discarded, 
cast-iron  water  pipes,  over  1J  feet  in  diameter.  They  are  used  very 
extensively  by  waterproofers  for  drying  and  heating  sand  and  gravel 
in  large  quantities.  Where  possible,  the  sand  or  gravel  is  dumped 
directly  on  the  pipes  as  shown,  otherwise  these  materials  are  shoveled 
on  until  a  pile,  2  or  3  feet  high,  rests  on  them.  A  wood  fire  is  built 
inside  of  these  pipes,  in  which  a 
natural  draft  is  always  present. 
When  the  sand  is  sufficiently  heat- 
ed, it  is  usually  screened  (see  man 
with  shovel  at  wheelbarrow)  before 
being  used.  Tig.  78  shows  an 
improvised  pipe  furnace  for  dry- 
ing, heating  and  screening  sand  in 
large  quantities. 

Salamander.  The  salamander 
shown  in  Fig.  79  is  used  for 
drying  bricks  which  are  intended 
for  brick-in-mastic  waterproofing, 
and  also  for  heating  enclosed 
areas  to  be  waterproofed'  in  cold 
weather.  Salamanders  are  usually 
made  of  J-  or  j^-inch  steel  plate 
and  equipped  with  heavy  cast-iron 
gratings.  They  come  in  several 
sizes,  the  most  common  being  17 
inches  in  diameter  by  20  inches 
high  and  20  inches  in  diameter  by 
24  inches  high. 

Wheel  Barrow.  A  steel-tray  wheel  barrow,  besides  serving  its 
obvious  purpose,  is  very  commonly  used  for  volume  measurements 
of  the  mineral  ingredients  entering  into  the  making  of  mastic  for 
waterproofing.  Such  a  wheel  barrow  is  usually  constructed  of 
Nos.  16  to  12  gauge  steel,  and  in  capacities  of  2J  to  6  cubic  feet. 

Concrete  Tampers.  The  tampers  shown  in  Fig.  80,  A ,  B  and  C, 
are  designed  to  insure  a  compact  concrete  mass.  The  tamping  process 
is  really  a  slicing  and  cutting  process  for  the  purpose  of  letting  air 
bubbles  out  of  the  concrete.  Ordinary  tamping  is  done  by  a  form 
of  tamper  shown  in  Fig.  80,  B.  For  facing  work,  the  gridiron  tamper 
in  Fig.  80,  A,  gives  excellent  results.  The  tamper  shown  at  C  is 
constructed  with  two  spacings. 


FIG.  79.— Iron  Salamander  Used  for 
Drying  and  Heating  tricks. 


182 


WATERPROOFING  ENGINEERING 


Trowels  and  Floats.  Fig.  81,  A,  represents  the  usual  form  of 
trowel  used  for  pointing  between  copings,  or  flashings  and  walls,  etc. 
Fig.  81,  B,  represents  the  usual  form  of  trowel  used  in  applying  and 
smoothing  waterproofed  plaster  and  mortar.  Fig.  81,  C,  is  a  wooden 
spreader  or  float  generally  used  for  spreading  and  floating  bitumi- 
nous-mastic floors,  sheet  mastic  waterproofing,  etc.  It  is  about  1 


81bs. 


FIG.  80.  —  Concrete  Tampers. 


foot  long,  4  inches  wide  and  2  inches  thick,  with  smooth  and  true 
faces  all  around.  In  using  the  float  its  beveled  edge  is  held  forward 
and  applied  in  a  somewhat  diagonal  direction  while  pressure  is  brought 
to  bear  on  the  handle.  It  is  not  possible  to  secure  the  same  fine, 
finished  surface  on  these  materials  with  an  iron  trowel  or  smoother. 
Cores  for  Felt  and  Fabric  Rolls.  Waterproofing  felt  and  fabric  is 
put  up  in  rolls  so  as  to  make  handling  easy  (see  Fig.  120).  In  ship- 


WATERPROOFING   IMPLEMENTS  AND.  MACHINERY        183 

ping,  hauling  and  storing,  these  rolls  \vould  be  badly  crushed,  warped, 
bent  and  wrinkled  but  for  the  solid  core  on  which  they  are  usually 
wound.  The  cores  are  sometimes  made  of  paste-board  roll  and 
slat  crates  but  most  often  of  solid  square  or  round  sticks.  Water- 


FIG.  81. 

A.  Mastic  trowel. 

B.  Mortar  Trowel. 

C.  Wood  Spreader  or  Float  for  Mastic  Floors. 

proofing  felts  are  often  rolled  up  without  any  cores,  but  waterproofing 
fabric  can  never  be  handled  without  cores.  The  various  types 
employed  are  illustrated  in  Fig.  82. 

Mechanical  Brick  Heater.     A  practical  and  economical  method 
of  drying  and  heating  bricks  is  by  the  use  of  an  iron  furnace,  or 


Wood 

2x2" 


Wood 
2"DIam. 


Cardboard 
4"Diam. 


Wood  Crate 
3 -2"  Blocks 


'  Box  Core 
3"x  3" 


FIG.  82. — Types  of  Cores  upon  which  Felt  and  Fabric  is  Rolled  for  Shipping. 


heater.*  This  heater  consists  of  a  rectangular  sheet-iron  box  about 
4  by  4  feet  and  8  feet  high.  On  opposite  sides  and  .at  different 
elevations  it  has  rectangular  openings  10  or  12  inches  high  and  4  feet 
wide.  To  the  bottom  of  these  openings  are  attached  hinged  doors. 
*  Designed  and  used  by  the  New  York  Roofing  Co. 


184  WATERPROOFING  ENGINEERING 

Gratings  inclined  about  45  degrees  connect  with  the  bottoms  of  the 
door  openings.  A  low,  flat,  iron,  box-like  salamander  placed  on  the 
ground  under  the  lowest  grating  completes  the  equipment.  The 
process  of  heating  the  bricks  is  commenced  by  kindling  a  charcoal 
fire  in  the  salamander,  and  placing  bricks  on  the  first  grating  through 
the  most  elevated  door  connected  therewith,  the  lower  one  remaining 
closed.  Then  bricks  are  placed  on  the  second  grating  and  finally 
on  the  third  grating.  By  the  time  this  is  done  the  bricks  on  the  first 
grating  are  sufficiently  dry  and  warm  and  may  be  dumped  from  the 
heater  into  a  wheel  barrow  or  other  conveyance  by  opening  the  door 
on  the  lower  level.  Then  the  second  and  third  doors  above  are 
opened  in  succession,  allowing  the  bricks  to  fall  out  automatically. 
With  this  heater,  14,000  to  20,000  bricks  per  day  can  be  dried  and 
heated  to  quite  a  high  temperature  and  without  soot. 


THE  CEMENT  GUN 

Fig.  83  illustrates  a  modern  type  of  cement  gun.  A  sectional 
view  is  shown  in  Fig.  84.  This  type  is  built  to  withstand  air-pressure 
up  to  60  pounds  per  square  inch.  The  following  description  will 
aid  in  understanding  its  operation: 

The  tanks  marked  in  the  figure  as  4  and  5  are  steel  sheet,  welded 
on  both  sides  and  riveted  to  flanges  as  shown.  The  tank  is  hinged 
to  the  cast-iron  base  to  permit  access  to  the  interior  for  cleaning. 
The  cone  valves  3  and  the  feed  wheel  6  are  of  cast  iron  with  a 
smooth  finish.  The  air  motor  9  drives  the  feed  wheel  through  a 
worm  and  worm  gear.  The  dry  materials,  mixed  in  the  proper 
proportions,  are  placed  in  both  tanks  through  the  open  valves, 
before  any  air  is  turned  on.  Then  the  upper  cone  valve  3  is  closed 
by  means  of  lever  2  and  compressed  air  is  admitted  through  cock  A, 
which  holds  the  cone  valve  in  place.  Cock  B  is  then  opened,  admit- 
ting air  through  a  gooseneck  and  the  outlet  valve  8.  Cock  C  is  then 
opened  which  makes  the  feed  wheel  6  revolve,  and  the  material  in 
each  pocket  of  same,  as  it  registers  with  the  gooseneck,  is  blown  out 
through  valve  8,  into  the  material  hose  attached  thereto,  to  the 
nozzle  where  the  water  from  a  separate  base  is  added. 

To  recharge  the  machine  it  is  not  necessary  to  stop  it,  as  the  lower 
cone  valve  3  is  held  in  the  position  shown  when  the  air  in  the  upper 
tank  is  exhausted.  The  upper  cone  valve  then  opens  and  a  new 
charge  is  put  into  the  machine.  The  operation  of  this  machine 
must  be  continuous  while  the  mortar  is  being  applied. 


WATERPROOFING  IMPLEMENTS  AND  MACHINERY        185 


FIG.  83. — Cement  Gun.     (Height,  69  Inches;    Floor  Space,  42  by  44  Inches; 

Weight,  1350  Ib.) 


186 


WATERPROOFING  ENGINEERING 


THE  GROUTING  MACHINE 

Grouting  machines  are  manufactured  in  several  sizes  to  with- 
stand presures  up  to  600  pounds  per  square  inch.     They  can  be 


made  to  stir  the  grout  mechanically,  or  by  compressed  air.  Fig.  85 
shows  a  small-sized  patented  grout  mixer  designed  for  mixing  grout 
by  compressed  air  only.  The  space  occupied  by  such  a  machine  is 


WATERPROOFING  IMPLEMENTS  AND   MACHINERY        187 

about  3  by  3  feet  and  4  feet  high.     The  average  batch  capacity  is 
about  4  cubic  feet. 

Referring  to  its  operation,  B  is  the  compressed  air  inlet.  Valves 
C,  D,  and  F  are  closed  and  door  A  opened.  The  sand  and  cement 
are  charged  through  the  door  A,  and  a  measured  quantity  of  water  is 
admitted  through  A  by  means  of  a  hose.  Then  the  door  A  is  closed. 
Valve  D  is  now  opened,  allowing  the  compressed  air  to  blow  in  at 
the  bottom  to  mix  the  grout.  This  keeps  the  mixture  agitated  and 


Blow  off  when  Mixing 

AN 


Grout  Discharge 
to  Place, 

FIG.  85. — Section  of  Ransome-Caniff  Grout  Mixer.     (Patented.) 

prevents  the  sand  and  cement  setting  into  and  choking  the  outlet, 
pipe  G.  During  this  operation,  the  blowoff  valve  K  must  be  open. 
When  the  batch  is  mixed,  valves  K  and  D  are  closed,  and  valve  C 
opened.  When  the  batch  is  to  be  ejected,  valve  F,  controlled  by 
handle  H,  is  opened  and  the  grout  discharged  through  a  hose  attached 
to  outlet  G.  Then  valves  C  and  F  are  closed,  the  excess  pressure 
allowed  to  blow  off  through  valve  K,  when  the  door  A  drops  open, 
and  the  machine  is  again  ready  to  be  charged. 


CHAPTER  VII 
TECHNICAL  AND   PRACTICAL  TESTS   ON  WATERPROOFING 

Necessity  of  Testing  Waterproofing  Materials.  Testing  of 
waterproofing  materials  is  necessary  to  insure  good  and  uniform 
products.  Representative  specimens  of  materials  to  be  used  should  be 
tested  in  the  laboratory  for  comparison  with  specified  requirements. 
Analysis  should  be  made  when  any  doubt  exists  regarding  the  true 
nature  of  the  material.  This  is  especially  true  of  tar  and  bituminous 
compounds  and  proprietary  products,  as  has,  no  doubt,  become 
evident.  Some  practical  field  tests  may  reveal  certain  undesirable 
qualities,  but  laboratory  tests  can  often  be  relied  upon  to  reveal 
more,  and  should  not  be  neglected. 

To  know  the  properties  of  materials  is  not  more  essential  than 
knowing  how  to  test  for  these  properties,  at  least  in  a  practical  way. 
In  the  light  of  present-day  knowledge  of  waterproofing  materials, 
it  is  necessary  for  the  engineer  to  be  acquainted  with  methods  of 
testing  and  to  be  able  to  correctly  interpret  results  of  tests.  Of 
equal  importance  to  the  tester  is  a  knowledge  of  the  significance  of 
the  tests  called  for  in  specifications.  For  this,  however,  both  techni- 
cal knowledge  and  experience  are  necessary. 

In  this  chaper  technical  tests  on  pitch  and  asphalt  are  briefly 
described  and  their  significance  explained;  also  tests  and  results 
on  the  impermeability  of  plain  and  waterproofed  concrete  and  cement 
mortars,  and  certain  practical  tests  related  to  general  waterproofing 
are  described.  The  results  of  some  of  the  tests  described  herein 
will  make  evident  certain  statements  of  facts  made  in  other  chapters. 
Particular  attention  is  directed  to  the  many  practical  tests  as  show- 
ing the  logical  way  of  aiding  the  engineer's  judgment  in  arriving  at 
conclusions  in  regard  to  the  adaptability  of  some  materials  for 
unusual  purposes. ,  Waterproofing  involves  comparatively  little 
theory,  which ,  perhaps,  explains  its  slow  progress,  and  its  continu- 
ance as  an  art  rather  than  as  an  exact  science. 

188 


TECHNICAL  AND   PRACTICAL  TESTS  ON   WATERPROOFING     189 


SIGNIFICANCE  AND  DESCRIPTION  OF  TECHNICAL  TESTS  ON  BITUMENS 

The  bitumens  form  the  most  important  and  widely  used. materials 
for  waterproofing.  It  will  be  well,  therefore,  to  describe  some  of  the 
laboratory  tests  made  on  this  class  of  materials  in  more  detail  than 
the  others. 

The  following  list  of  tests  includes  all  those  of  more  or  less  value 
in  determining  and  recording  the  characteristics  of  tar  and  bituminous 
materials  used  for  waterproofing  purposes: 

Coal-tar  Pitch.  Specific .  gravity  at  60  deg.  Fahr.  (15.5  deg. 
Cent.)  or  77  deg.  Fahr.  (25  deg.  Cent.). 

Flash  point. 

Solubility  in  carbon  disulphide  (082). 

Penetration  (consistency)  at  39  deg.  Fahr.  (4  deg.  Cent.)  and 
77  deg.  Fahr.  (25  deg.  Cent.). 

Flow  point. 

Melting-point. 

Loss  on  evaporation  at  325  deg.  Fahr.  (163  deg.  Cent.). 

Penetration  (consistency)  of  residue  at  39  deg.  Fahr.  (4  deg. 
Cent.),  77  deg.  Fahr.  (25  deg.  Cent.). 

Melting-point  of  residue. 

Free  carbon  content. 

Ash  test. 

Asphalt.  Specific  gravity  at  60  deg.  Fahr.  (15.5  deg.  Cent.), 
or  77  deg.  Fahr.  (25  deg.  Cent.). 

Flash  point. 

Solubility  in  carbon  disulphide  (082). 

Solubility  in  carbon  tetrachloride  (CCU). 

Solubility  in  petroleum  naphtha. 

Penetration  (consistency)  at  39  deg.  Fahr.  (4  deg.  Cent.)  and  77 
deg.  Fahr.  (25  deg.  Cent.). 

Melting-point. 

Ductility  at  39  deg.  Fahr.  (4  deg.  Cent.)  and  77  deg.  Fahr.  (25 
deg.  Cent.). 

Fixed  carbon  content  and  paraffin  content.* 

Loss  on  evaporation  at  325  deg.  Fahr.  (163  deg.  Cent.). 

Penetration  (consistency)  of  residue  at  39  deg.  Fahr.  (4  deg. 
Cent.),  77  deg.  Fahr.  (25  deg.  Cent.). 

Melting-point  of  residue. 

*  The  fixed  carbon  and  paraffin  content  tests  are  of  little  practical  value, 
but  are  included  here  because  this  fact  is  not  yet  generally  so  accepted. 


190  WATERPROOFING  ENGINEERING 

Ductility  of  residue  at  39  deg.  Fahr.  (4  deg.  Cent.),  77  deg.  Fahr. 

(25deg.Cent.). 

Specific  Gravity.  Specific  gravity  is  mainly  used  to  differentiate 
between  different  tars  or  bitumens  and  as  a  means  of  identification. 
The  temperature  at  which  the  tar  or  bitumen  is  tested  is  a  governing 
factor  in  the  determination  of  its  specific  gravity.  This  temperature, 
which  has  been  standardized,  and  always  accompanies  the  specific 
gravity  value,  is  either  60  or  77  deg.  Fahr.  (15.5  or  25  deg.  Cent.), 
selected  arbitrarily.  The  specific  gravity  of  the  semi-solid  asphalts 
varies  with  their  origin,  mode  and  degree  of  refinement,  and  lies 
between  .87  and  1.21  at  77  deg.  Fahr.  The  specific  gravity  of  the 
tars  varies  with  the  method  of  manufacture  and  degree  of  distilla- 
tion, and  lies  between  1.10  and  1.25  at  60  deg.  Fahr. 

The  specific  gravity*  of  thin  fluid  pitches  or  bitumens  is  usually 
determined  by  the  hydrometer  method,  which  consists  in  selecting 
the  proper  hydrometer,  inserting  it  in  the  material  at  77  deg.  Fahr. 
(25  deg.  Cent.)  and  reading  the  specific  gravity  off  the  scale  to  the 
third  decimal  place. 

The  specific  gravity  of  hard,  solid,  bitumens  is  determined  by  the 
displacement  method,  i.e.,  suspending  a  small  piece  of  the  bitumen 
by  means  of  a  silk  thread  from  the  hook  of  one  of  the  pan  supports 
of  an  analytical  balance,  about  1J  inches  above  the  pan  and  weighed. 
This  is  weight  "  a."  It  is  then  weighed  immersed  in  water  at  25  deg. 
Cent,  and  this  weight  is  called  "  6."  The  specific  gravity  of  the. 

a 

bitumen  is  then  equal  to  — — 

a-b. 

The  specific  gravity  of  viscous  and  semi-solid  bitumens  is  usually 
determined  by  the  pyknometer  method,  which  requires  the  following 
equipment: 

A  large  metal  kitchen  spoon,  a  steel  spatula  or  kitchen  knife, 
Bunsen  burner  and  rubber  tubing,  one  250-c.c.  low-form  glass 
beaker,  a  chemical  thermometer  reading  from  18  deg.  Fahr.  to 
230  deg.  Fahr.  (-10  deg.  Cent,  to  110  deg.  Cent.),  a  special 
pyknometer  (Fig.  86),  an  analytical  balance,  capacity  100  grams, 
sensitive  to  0.1  mg. 

The  pyknometer  consists  of  a  fairly  heavy,  straight-walled  glass 
tube,  70  mm.  long  and  22  mm.  in  diameter,  carefully  ground  to 
receive  an  accurately  fitting  solid  glass  stopper  with  a  hole  of 
1.6  mm.  bore  in  place  of  the  usual  capillary  opening.  The  lower 
part  of  this  stopper  is  made  concave  in  order  to  allow  all  air 

*  Methods  for  the  examination  of  bituminous  road  materials.  Bulletin  No. 
314,  U.  S.  Dept.  of  Agriculture. 


TECHNICAL  AND  PRACTICAL  TESTS  ON   WATERPROOFING     191 


j  —  n  —  i 


bubbles  to  escape  through  the  bore.  The  depth  of  the  cup-shaped 
depression  is  4.8  mm.  at  the  center.  The  stoppered  tube  has  a 
capacity  of  about  24  c.c.  and  when  empty  weighs  about  28  grams. 

When  working  with  semi-solid  bitumens  which  are  too  soft  to  be 
broken  and  handled  in  fragments,  the  following  method  of  deter- 
mining their  specific  gravity  is  employed.  The  clean,  dry  pyknometer 
is  first  weighed  empty  and  this  weight  is  called  "  a."  It  is  then  filled 
in  the  usual  manner  with  freshly  distilled  water  at  77  deg.  Fahr. 
(25  deg.  Cent.),  and  the  weight  is  again  taken  and  called  "  b." 
A  small  amount  of  the  bitumen  should  be  placed  in  the  spoon  and 
brought  to  a  fluid  condition  by  the  gentle  appli- 
cation of  heat,  with  care  that  no  loss  by 
evaporation  occurs.  When  sufficiently  fluid, 
enough  is  poured  into  the  dry  pyknometer, 
which  may  also  be  warmed,  to  fill  it  about 
half  full,  without  allowing  the  material  to 
touch  the  sides  of  the  tube  above  the  desired 
level.  The  tube  and  contents  are  then  allowed 
to  cool  to  room  temperature,  after  which  the 
tube  is  carefully  weighed  with  the  stopper. 
The  weight  is  called  "  c."  Distilled  water,  at 
77  deg.  Fahr.  (25  deg.  Cent.),  is  then  poured 
in  until  the  pyknometer  is  full.  After  this  the 
stopper  is  inserted,  and  the  whole  cooled  to  77 
deg.  Fahr.,  by  a  30-minute  immersion  in  a  beaker 
of  distilled  water  maintained  at  this  tempera- 
ture.  All  surplus  moisture  is  then  removed 
with  a  soft  cloth,  and  the  pyknometer  and  con- 
tents  are  weighed.  This  weight  is  called  "  d." 
From  the  weights  obtained  the  specific  gravity  of  the  bitumen  may 
be  readily  calculated  by  the  following  formula: 

Specific  gravity  at  77  deg.  Fahr./77  deg.  Fahr.  =  -  -  ^—  ^-  —  -. 

(b-a)-(d-c) 

Flash  Point.  The  flash  point  of  an  asphalt  determines  the  pos- 
sibility of  explosions  in  the  melting  kettles  and  general  fire  risk.  It 
is  the  temperature  at  which  volatile  oils  are  given  off  in  a  gaseous 
state  and  which  may  catch  fire.  This  is  guarded  against  by  keeping 
the  flash  point  as  high  as  possible,  that  is,  refining  the  asphalts 
so  as  to  exclude  as  much  volatile  oil  as  practicable.  An  asphalt 
with  a  flash  point  below  400  deg.  Fahr.  is  not  ordinarily  used. 

Although  for  ordinary  purposes  the  open-cup  method  for  deter- 
mining the  flash  and  burning-points  of  tars  and  bituminous  materials 


Uged  to  obtain 
Specific  Gravity  of 
Bitumens. 


192 


WATERPROOFING  ENGINEERING 


is  reasonably  accurate,  the  closed-cup  method  described  below  is  to 
be  preferred. 

The  oil  tester  consists  of  a  copper  oil  cup  (Fig.  87)  having  a 
capacity  of  about  300  c.c.  It  is  heated  in  a  water  or  oil  bath  by 
a  small  Bunsen  flame.  The  cup  is  provided  with  a  glass  cover, 

carrying  a  thermometer  and  a  hole 
for  inserting  the  testing  flame.  The 
testing  flame  is  obtained  from  a  jet 
of  gas  passed  through  a  piece  of  glass 
tubing,  and  is  about  5  mm.  long1. 

The  flash  test  is  made  as  follows: 
The  oil  cup  is  first  removed  and  the 
bath  filled  with  water  or  cottonseed 
oil,  depending  on  the  volatile  nature 
of  the  material  tested.  The  oil  cup 
is  replaced  and  filled  with  the  material 
to  be  tested  to  within  3  mm.  of  the 
flange  joining  the  cup  and  the  vapor 
chamber  above.  The  glass  cover  is 
then  placed  on  the  oil  cup  and  the 
thermometer  adjusted  so  that  its  bulb 
is  just  covered  by  the  bituminous 
material.  The  Bunsen  flame  is  then 
applied  in  such  a  manner  that  the 
temperature  of  the  material  in  the  cup 
is  raised  at  the  rate  of  about  9  deg. 
Fahr.  (5  deg.  Cent.)  per  minute. 
From  time  to  time  the  testing  flame 
is  inserted  in  the  opening  in  the  cover 
to  about  half  way  between  the  surface 
of  the  material  and  the  cover.  The 
appearance  of  a  faint  bluish  flame 
over  the  entire  surface  of  the  bitu- 
minous material  will  show  that  the 
flash  point  has  been  reached  and  the 

temperature  at  this  point  is  taken.  The  burning-point  of  the  material 
may  be  obtained  by  removing  the  glass  cover  and  replacing  the 
thermometer  in  a  wire  frame.  The  temperature  is  raised  at  the  same 
rate  and  the  material  tested  as  before.  The  temperature  at  which 
the  material  ignites  and  burns  is  taken  as  the  burning-point. 

Solubility  in  Carbon  Bisulphide.  In  nearly  all  asphalts  there  is  a 
pertain  quantity  of  insoluble  bitumen  present.  This  insoluble  bitu- 


Fia.  87.— New  York  State  Board 
of  Health  Oil  Tester. 


TECHNICAL  AND  PRACTICAL  TESTS  ON   WATERPROOFING     193 

men  lessens  the  cementing  value  of  the  remainder  of  the  asphalt, 
raises  its  melting-point,  causes  it  to  become  brittle  at  low  tempera- 
tures, and  otherwise  impairs  its  suitability  for  waterproofing  purposes. 
A  pure  asphalt  of  uniform  consistency,  containing  the  highest  per 
cent  of  soluble  bitumen,  is  the  most  workable  and  durable,  and  the 
solubility  test  in  carbon  disulphide  aids  the  chemist  in  deciding 
these  points.  A  determination  of  the  amount  of  pure  bitumen 
present  in  any  specimen  by  this  test  should  not  show  less  than  95 
per  cent. 

The  test  consists  in  dissolving  the  bituminous  material  in  car- 
bon disulphide,  and  recovering  any  insoluble  matter  by  filtering 
the  solution  through  an  asbestos  felt  filter.  This  felt  is  carefully 
placed  in  the  bottom  of  a  Gooch  crucible,  washed  several  times  with 
water,  and  drawn  firmly  against  the  bottom  of  the  crucible  by 
suction.  The  crucible  used  for  this  determination  should  be  4.4 
cm.  wide  at  the  top,  tapering  to  3.6  cm.  at  the  bottom,  and  2.5  cm. 
deep.  The  crucible  containing  the  filter  is  first  placed  in  a  drying 
oven  for  a  few  minutes,  removed  and  ignited  to  red  heat  over  a 
Bunsen  burner,  cooled  in  a  desiccator  and  weighed. 

Two  grams  of  bituminous  material  is  then  placed  in  a  flask, 
which  has  been  weighed  previously,  and  the  accurate  weight  of  the 
sample  obtained.  One  hundred  cubic  centimeters  of  chemically 
pure  carbon  disulphide  is  poured  into  the  flask,  in  small  portions, 
with  continual  agitation,  until  all  lumps  disappear  and  nothing 
adheres  to  the  bottom.  The  flask  is  then  corked  and  set  aside 
for  fifteen  minutes  to  allow  settlement  of  the  insoluble  material. 

This  solution  should  then  be  decanted  through  the  felt  filter  in 
the  Gooch  crucible  without  stirring  up  any  precipitate  that  may  have 
settled  down.  The  sides  of  the  flask  should  now  be  washed  down 
with  a  small  quantity  of  carbon  disulphide,  after  which  the  whole  is 
poured  on  the  felt  and  suction  applied  until  there  is  practically 
no  odor  of  carbon  disulphide  in  the  crucible.  The  crucible  and  con- 
tents should  then  be  dried  at  212  deg.  Fahr.  (100  deg.  Cent.)  for 
about  twenty  minutes,  cooled  in  a  desiccator  and  weighed.  The 
weight  of  insoluble  matter  may  include  both  organic  and  mineral 
matter.  The  former  must  be  burned  off  by  ignition  at  a  red  heat, 
thus  leaving  a  mineral  matter  or  ash  which  is  weighed  when  cool. 
The  difference  between  the  total  weight  of  the  material  insoluble  in 
carbon  disulphide  and  the  weight  of  substance  taken  equals  the 
total  bitumen.  The  percentage  weights  are  calculated  as  total 
bitumen,  and  insoluble  matter,  on  the  basis  of  the  weight  of  material 
taken  for  analysis.  Further  detailed  information  for  those  partic- 


194  WATERPROOFING  ENGINEERING 

ularly  interested  in  this  test  will  be  found  in  the  Transactions  of 
the  American  Society  of  Civil  Engineers,  Vol.  82,  p.  1450  (1918). 

Solubility  in  Carbon  Tetrachloride.  The  solubility  test  in  carbon 
tetrachloride  shows  whether  or  not  the  asphalt  has  been  overheated 
in  refining.  The  greater  the  percentage  of  insoluble  bitumen,  the 
greater  the  overheating;  in  other  words,  it  indicates  the  amount 
of  incipient  destruction  that  the  asphalt  has  undergone.  This  test 
also  determines  the  amount  of  other  impurities  present  in  the  asphalt. 
The  amount  of  pure  bitumen  (the  soluble  part)  present  in  any  given 
specimen  should  not  be  less  than  95  per  cent. 

The  test  is  conducted  in  exactly  the  same  manner  as  described 
for  "  Solubility  in  Carbon  Bisulphide,"  except  that  100  c.c.  of 
chemically  pure  carbon  tetrachloride  is  used  in  place  of  carbon 
disulphide,  and  the  percentage  of  bitumen  insoluble  in  carbon  tetra- 
chloride is  reported  on  the  basis  of  the  bitumen  taken  as  100,  the 
quantity  of  the  bitumen  having  been  determined  by  the  method 
previously  described. 

Solubility  in  Petrolic  Ether*  (Petroleum  Naphtha).  The  solu- 
bility test  in  petrolic  ether  is  to  determine  the  per  cent  of  petroline 
present  in  asphalt,  which  material  is  considered  to  give  the  viscous  or 
adhesive  quality  to  the  asphalt.  This  test  also  shows  the  amount 
of  true  bitumen  in  the  asphalt,  i.e.,  the  amount  of  hydrocarbon 
called  "  asphaltine."  Asphaltine  is  supposed  to  possess  the  greatest 
durability  and  resistance  to  deteriorating  agents ;  it  also  gives  hard- 
ness to  the  asphalt.  The  petrolic  ether  dissolves  out  the  petroline, 
leaving  the  insoluble  asphaltine.  A  reasonably  good  asphalt  will  be 
greater  than  66  per  cent  soluble  in  petrolic -ether  of  88  deg.  Baume. 

This  determination  is  made  in  the  same  general  manner  as  the 
test  for  solubility  in  carbon  disulphide,  except  that  100  c.c.  of  86 
to  88  deg.  Baume  paraffin  naphtha,  at  least  85  per  cent  distilling 
between  95  and  149  deg.  Fahr.  (35  and  65  deg.  Cent.)  is  employed 
as  a  solvent  instead  of  carbon  disulphide.  Considerable  difficulty 
is  sometimes  experienced  in  breaking  up  some  of  the  heavy  semi- 
solid  bitumens;  the  surface  of  the  material  is  attacked,  but  it  is 
necessary  to  remove  some  of  the  insoluble  matter  in  order  to  expose 
fresh  material  to  the  action  of  the  solvent.  It  is,  therefore,  ad- 
visable to  heat  the  sample  after  it  is  weighed,  allowing  it  to  cool 
in  a  thin  layer  around  the  lower  part  of  the  flask.  If  difficulty 
is  still  experienced  in  dissolving  the  material,  a  rounded  glass  rod 
will  be  found  convenient  for  breaking  up  the  undissiolved  particles. 
Not  more  than  one-half  of  the  total  amount  of  naphtha  required 
*U.  S.  Dept.  of  Agriculture.  Bulletin  No.  314,  Dec.  10,  1915,  p.  28. 


TECHNICAL  AND   PRACTICAL  TESTS  ON  WATERPROOFING     195 

should  be  used  until  the  sample  is  entirely  broken  up.  The  balance 
of  the  100  c.c.  is  then  added,  and  the  flask  is  twirled  a  moment  in 
order  to  mix  the  contents  thoroughly,  after  which  it  is  corked  and 
set  aside  for  thirty  minutes. 

In  making  the  filtration  the  utmost  care  should  be  exercised  to 
avoid  stirring  up  any  of  the  precipitate,  in  order  that  the  filter  may 
not  be  clogged  and  that  the  first  decantation  may  be  as  complete 
as  possible.  The  sides  of  the  flask  should  then  be  quickly  washed 
down  with  naphtha  and,  when  the  crucible  has  drained,  the  bulk  of 
insoluble  matter  is  brought  upon  the  felt.  Suction  may  be  applied 
when  the  filtration  by  gravity  almost  ceases,  but  should  be  used 
sparingly,  as  it  tends  to  clog  the  filter  by  packing  the  precipitate 
too  tightly.  The  material  on  the  felt  should  never  be  allowed 
to  run  entirely  dry  until  the  washing  is  completed,  as  shown  by  the 
colorless  filtrate.  When  considerable  insoluble  matter  adheres  to 
the  flask  no  attempt  should  be  made  to  remove  it  completely.  In 
such  cases  the  adhering  material  is  merely  washed  until  free  from 
soluble  matter,  and  the  flask  is  dried  with  the  crucible  at  100° 
deg.  Cent,  for  about  one  hour,  after  which  it  is  cooled  and  weighed. 
The  percentage  of  bitumen  insoluble  is  reported  upon  the  basis  of 
total  bitumen  taken  as  100. 

The  difference  between  the  material  insoluble  in  carbon  disul- 
phide  and  in  the  naphtha  is  the  bitumen  insoluble  in  the  latter. 
Thus,  if  in  a  certain  instance  it  is  found  that  the  material  insoluble 
in  carbon  disulphide  amounts  to  1  per  cent  and  that  10.9  per  cent 
is  insoluble  in  naphtha,  the  percentage  of  bitumen  insoluble  would 
be  calculated  as  follows: 

Bitumen  insoluble  in  naphtha     10.9  —  1     9.9 

—  = =  —  =  10  per  cent. 

Total  bitumen  100-1      99 

Penetration  Test.*  Consistency  of  an  asphalt  is  a  measure, 
especially  in  commerce,  of  its  hardness  and  softness  at  various  tem- 
peratures, and  this  property  is  usually  determined  by  the  penetra- 
tion test.  The  greater  the  penetration,  the  softer  is  the  bitumen. 
All  coal-tar  pitches  and  asphalts  have  the  property  of  being  softened 
by  heat  and  hardened  by  cold,  hence  it  is  necessary  to  determine  to 
what  degree  they  are  so  affected.  It  is  evident  that  the  less  a  pitch 
or  asphalt  is  changed  in  consistency  by  changes  in  temperature,  the 
more  desirable  it  is  as  a  waterproofing  material.  But  what  the 
penetration  of  coal-tar  pitch  or  asphalt  for  waterproofing  should  be 
depends  largely  on  the  specific  use  they  will  be  put  to. 

*  Journal  of  Industrial  Engineering  Chemistry,  Vol.  6,  No.  2,  February,  1914. 


196 


WATERPROOFING  ENGINEERING 


The  test  is  performed  on  a  standard  machine  called  a  pene- 
trometer.  Penetrometers  consist  essentially  of  a  needle  of  specified 
size  (Roberts  No.  2)  fixed  in  a  rod,  the  rod  and  needle  being  of, 
or  loaded  to,  definite  weights.  A  clamp  on  the  body  of  the  instrument 
holds  the  rod  with  the  needle,  which,  on  being  released,  allows  the 
latter  to  penetrate  as  nearly  as  possible  without  friction.  A  device 
for  measuring  the  amount  the  needle  has  penetrated  after  it  has  been 
released  for  a  specified  time  and  again  grasped  by  the  clamp  is  also 

included.  (The  Dow  pene- 
trometer  is  constructed  on 
this  basis.)  The  penetration 
is  expressed  in  hundredths  of 
a  centimeter,  though  it  is  not 
always  designated  so.  Pene- 
trations are  most  commonly 
made  at  77  deg.  Fahr.  (25  deg. 
Cent.),  with  the  needle  loaded 
to  100  grams  penetrating  for 
five  seconds.  In  order  to 
ascertain  the  extent  a  bitumen 
will  harden  when  chilled  to  32 
deg.  Fahr.  (0  deg.  Cent.), 
penetrations  are  frequently 
made  at  this  temperature  with 
the  needle  loaded  to  200  grams 
penetrating  for  one  minute. 
A  new  form  of  penetrometer 
electrically  controlled  and 
timed  is  shown  in  Fig.  88.  A 
new  and  much  more  accurate 
machine  of  this  type,  called  a 
consistometer,  in  which  the 
needle  is  replaced  by  a  rod  and 

penetration  or  consistency  is  measured  by  volume  displacement,  is 
described  in  the  Proceedings  of  the  American  Society  for  Testing 
Materials,  Vol.  11,  1911.  For  a  more  detailed  description  of  the 
Penetration  Test  see  Transactions  of  the  American  Society  of  Civil 
Engineers,  Vol.  82,  p.  1454  (1918). 


FIG.  88. — Electrically  Controlled 
Penetrometer. 


TECHNICAL  AND  PRACTICAL  TESTS  ON   WATERPROOFING     197 


METHODS  OF  DETERMINING  MELTING-POINTS  OF  BITUMENS 

There  are  nine  or  more  different  methods  of  obtaining  the  melt- 
ing-point of  bitumen,  giving  results  varying  by  as  much  as  30  and 
40  deg.  Fahr.  What  causes  the  real  trouble,  though,  is  that  chemists 
are  at  variance  as  to  which  method  is  most  nearly  correct.  The 
technique  of  the  methods  differs  so  considerably  that  it  is  difficult 
or  impossible  to  note  any  definite  relation  between  the  results  obtained 
with  each  method. 

But,  as  a  matter  of  fact,  all  methods  are  more  or  less  incorrect. 
They  all  depend  on  varying,  arbitrary  factors  and  special  technique. 
They  all  attempt  to  determine  the  melting-point  of  materials  that 
have  no  melting-point.  Pitch  and  asphalt  have  no  melting-point 
for  the  reason  that  they  are  composed  of  complex  mixtures  of  hydro- 
carbons, which  are  of  indefinite  consistence  and  specific  gravity. 

Were  it  possible  to  measure  in  absolute  units  the  fluidity  of  a 
-pitch  or  asphalt,  this  would  furnish  the  ideal  method,  but  as  this 
seems  unattainable  it  would  be  advisable  to  select  one  method 
possessing  the  most  practicable  apparatus  and  technique.  Or  per- 
haps a  new  method  could  be  evolved  embodying  the  good  features 
of  all  the  present  ones.  Up  to  the  present  time  nothing  has  been 
done  to  co-ordinate  these  methods. 

However,  one  thing  is  certain,  any  method,  the  results  of  which 
are  influenced  by  the  specific  gravity  of  the  material  tested  is 
wrong.  This  refers  particularly  to  what  is  known  as  the  "  Cube-in- 
water  Method,"  described  below.  For  instance,  the  average  specific 
gravity  of  asphalt  derived  from  paraffin  petroleum  is  0.961;  from 
asphaltic  petroleum,  1.004.  The  buoyant  effect  of  the  material 
whose  specific  gravity  is  so  nearly  unity  is  obvious,  hence  no  worth- 
while melting-point  is  found  by  the  cube-in-water  method.  This 
is  equally  the  case  when  applied  to  coal-tar  pitch,  whose  specific 
gravity  varies  with  the  method  of  manufacture  or  reduction  as 
follows:  *  Gas-house  tars,  1.22;  coke-oven  tars,  1.18;  water-gas 
tars,  1.10.  A  standard  method  of  finding  the  melting-point  of 
bitumens  ought  to  be  established  for  general  use  for  all  laboratories; 
or  else  it  should  become  the  general  practice  to  state  the  method 
whenever  the  melting-point  of  a  bitumen  is  given,  otherwise,  as  at 
present,  this  value  is  practically  meaningless. 

Nearly  all  the  other  properties  of  pitch  or  asphalt  are  modified 
by  the  melting-point.  It  is,  in  fact,  a  measure  of  the  fluidity,  con- 

*  "  Some  experiments  on  Technical  Bitumens,"  by  S.  R.  Church,  American 
Society  for  Testing  Materials,  April,  1915. 


198  WATERPROOFING  ENGINEERING 

sistency  and  ductility  of  these  materials.  But  because  it  is  an 
arbitrary  value,  dependent  to  a  great  extent  on  the  method  of  test, 
it  is  not  as  reliable  as  its  importance  warrants.  The  nine  methods 
explained  below,  are  more  or  less  used  in  industrial  plants  and 
laboratories,  but  no  one  method  predominates.  These  are: 

1.  Ring-and-ball  Method. 

2.  Cube-in-air  Method. 

3.  Cube-in-water  Method. 

4.  Kraemer-and-Sarnow  Method. 

5.  New  York  Testing  Laboratory  Method. 

6.  Mabery-Sieplein  Method. 

7.  Richardson  Method. 

8.  General  Electric  Method. 

9.  Drop  Point  Test. 

Ring-and-ball  Method.  The  apparatus  of  the  C.  I.  Robertson 
or  the  ring-and-ball  method  consists  of  a  brass  ring  f  inch  in  diam- 
eter, J-inch  deep,  ^-inch  wide;  a  steel  ball  f  inch  in  diameter, 
weighing  350  grams;  a  standard  thermometer;  a  glass  beaker, 
about  600-c.c.  capacity.  The  test  is  made  as  follows: 

Press  the  ring  full  of  the  bitumen,  cutting  it  off  slightly  with  a 
hot  knife.  Place  the  ball  in  the  center  of  the  ring  and  suspend 
the  apparatus  in  a  beaker  of  water,  the  ring  and  ball  being  about 
1  inch  from  the  bottom  of  the  beaker;  also  suspend  a  thermometer 
in  the  beaker  of  water  to  the  same  depth.  Heat  up  at  the  rate  of 
9  deg.  Fahr.  (5  deg.  Cent.)  per  minute.  The  melting-point  is  that 
temperature  at  which  the  ball  drops  through  the  ring  (and  reaches 
the  bottom  of  the  beaker).  The  bitumen  in  the  ring  usually  sags 
down  before  the  melting-point  is  reached,  but  the  temperature  of 
the  water  at  the  time  the  ball  reaches  the  bottom  of  the  beaker 
is  the  temperature  recorded  as  the  melting-point. 

For  testing  bitumen  having  a  melting-point  above  110  deg. 
Fahr.  (43  deg.  Cent.)  the  sample  should  first  be  cooled  to  50  or  77 
deg.  Fahr.  (10  or  25  deg.  Cent.).  For  testing  bitumen  having  a 
melting-point  above  210  deg.  Fahr.  (99  deg.  Cent.)  the  sample  should 
be  cooled  to  60  or  100  deg.  Fahr.  (15.5  or  38  deg.  Cent.). 

Cube-in-air  Method.  The  material  under  examination  should 
be  melted  in  a  spoon  by  the  gentle  application  of  heat  until  suffi- 
ciently fluid  to  pour  readily.  Care  shall  be  taken  that  it  suffers  no 
appreciable  loss  by  volatization.  It  shall  then  be  poured  into  a 
12.7-mm.  (0.5-inch)  brass  cubical  mold,  which  shall  have  been 
amalgamated  with  mercury  and  shall  be  placed  on  an  amalgamated 


TECHNICAL  AND   PRACTICAL   TESTS  ON   WATERPROOFING     199 

brass  plate.     The  hot  material  shall  slightly  more  than  fill  the  mold, 
and,  when  cooled,  the  excess  shall  be  cut  off  with  a  hot  spatula. 

After  cooling  to  room  temperature,  the  cube  shall  be  removed 
from  the  mold  and  fastened  on  the  lower  arm  of  a  No.  10  wire  (B.  and 
S.  gauge),  bent  at  right  angles  at  one  end  and  suspended  beside  a 
thermometer  in  a  covered  Jena  glass  beaker  having  a  capacity  of 
400  c.c.  (13.526  ounces),  which  shall  be  placed  in  a  water  bath, 
or,  for  high  temperatures,  a  cottonseed-oil  bath.  The  wire  shall  be 
passed  through  the  center  of  two  opposite  faces  of  the  cube,  which 
shall  then  be  suspended  with  its  base  25.4  mm.  (1  inch)  above  the 
bottom  of  the  beaker.  The  water  or  oil  bath  shall  consist  of  an 
800-c.c.  (27.051  ounces)  low-form  Jena  glass  beaker  suitably 
mounted  for  the  application  of  heat  from  below.  The  beaker  in 
which  the  cube  is  suspended  shall  be  of  the  tall-form  Jena  type, 
without  lip.  The  metal  cover  shall  have  two  openings.  A  cork, 
through  which  passes  the  long  arm  of  the  wire,  shall  be  inserted  in 
one  hole  and  the  thermometer  in  the  other.  The  bulb  of  the  ther- 
mometer shall  be  just  level  with  the  cube  and  at  an  equal  distance 
from  the  side  of  the  beaker. 

After  the  test  specimen  shall  have  been  placed  in  the  apparatus, 
the  liquid  in  the  outer  vessel  shall  be  heated  in  such  a  manner  that 
the  thermometer  registers  an  increase  of  9  deg.  Fahr.  (5  deg.  Cent.) 
per  minute.  The  temperature  at  which  the  bituminous  material 
touches  the  bottom  of  the  beaker  shall  be  taken  as  the  melting-point. 
Determinations  made  in  the  manner  described  shall  not  vary  more 
than  3.6  deg.  Fahr.  (2  deg.  Cent.)  for  successive  trials  on  the  same 
material.  At  the  beginning  of  this  test  the  temperature  of  both 
bituminous  material  and  bath  shall  be  approximately  at  77  deg. 
Fahr.  (25  deg.  Cent.). 

Cube-in-water  Method.  The  cube-in-water  method  consists  of 
(1)  the  use  of  apparatus  shown  in  Fig.  89;  (2)  the  manipulation  of 
same,  as  follows.  (For  bitumens  with  a  melting-point  of  110  deg. 
to  170  deg.  Fahr.  (43  to  77  deg.  Cent.)).  A  clean,  well-shaped  J-inch 
cube  of  the  bitumen  is  formed  in  the  mold,  as  described  under  the 
cube-in-air  method  above,  placed  on  the  hook  of  the  No.  12  wire 
and  suspended  in  a  600-c.c.  beaker,  so  that  the  bottom  of  the  bitumen 
is  1  inch  above  the  bottom  of  the  beaker.  The  bitumen  should 
remain  five  minutes  in  400  c.c.  of  water  at  a  temperature  of  60  deg. 
Fahr.  (15.5  deg.  Cent.)  before  heat  is  applied.  Apply  heat  in  such 
a  manner  that  the  temperature  of  the  water  is  raised  9  deg.  Fahr. 
(5  deg.  Cent.)  per  minute.  The  temperature  recorded  by  the  ther- 
mometer (which  is  at  the  same  depth  as  the  bitumen  when  the  test 


200 


WATERPROOFING  ENGINEERING 


is  started),  at  the  instant  the  bitumen  touches  the  bottom  of  beaker 
is  considered  the  melting-point.  For  bitumens  with  a  melting- 
point  below  110  deg.  Fahr.  (43  deg.  Cent.)  the  same  method  can  be 
used  except  that  at  the  start  the  water  should  have  a  temperature 
of  40  deg.  Fahr.  (4  deg.  Cent.).  For  bitumens  170  deg.  Fahr.  (77 
deg.  Cent.)  up,  cottonseed  oil  should  be  substituted  for  water, 
otherwise  the  method  remains  the  same. 


MELTING-POINT  TEST 
No.  1.     Pitch  Mould  (Special). 
No.  2.     Hook;  Made  of  #  12  Copper  Wire. 
No.  3.     Thermometer. 

FIG.  89. — Apparatus  for  Determining  the   Melting-point  of   Bitumen  by  the 
Cube-in-water  Method. 


Kraemer-and-Sarnow  Method.*  The  Kraemer-and-Sarnow 
method  of  making  the  melting  point  test  for  asphalts,  tars,  etc.,  is  as 
follows:  Some  asphalt  in  a  layer  10  mm.  thick  is  melted  in  a  beaker 
contained  in  an  oil  bath.  Into  this  is  dipped  an  open-end  glass  tube 
10  cm.  long  and  6  or  7  mm.  internal  diameter.  The  upper  end  of 
the  tube  is  closed  with  the  finger,  the  tube  is  removed  and  the 
asphalt  is  allowed  to  solidify  in  the  tube  while  it  is  held  horizon- 
*  Peckhan's  "  Solid  Bitumens,"  p.  272. 


TECHNICAL  AND   PRACTICAL  TESTS  ON   WATERPROOFING    201 

tally  and  rotated.  When  the  asphalt  has  set  the  portion  adhering 
to  the  outside  is  removed.  The  length  of  the  column  inside  the 
tube  will  be  about  5  mm.  On  top  of  this  is  poured  5  grams  of 
mercury.  The  -tube  containing  the  asphalt  and  mercury  is  then 
suspended  in  a  beaker  full  of  oil  or  water  resting  in  another  beaker 
also  full  of  oil  or  water.  The  inner  beaker  contains  a  thermometer, 
the  bulb  of  which  stands  at  the  same  level  as  the  asphalt.  The  outer 
beaker  is  heated  by  means  of  a  small  flame.  The  temperature  of  the 


FIG.  90. — Apparatus  for  the  Determination  of  the  Melting-point  of  Bitumen 
by  the  New  York  Testing  Laboratory  Method. 


asphalt  and  thermometer  being  thus  raised  uniformly  at  the  rate  of 
9  deg.  Fahr.  (5  deg.  Cent.)  per  minute. 

The  temperature  recorded  when  the  mercury  falls  through  the 
layer  of  asphalt  is  taken  as  the  melting-point.  This  method  depends 
for  its  accuracy  upon  the  diameter  of  the  tube,  the  thickness  of  the 
asphalt  and  the  height  of  the  mercury  in  the  tube  above  the  asphalt. 

New  York  Testing  Laboratory  Method.  The  air  method  for 
determining  the  melting-point  of  semi-solid  or  solid  bitumens  requires 
the  apparatus  shown  in  Fig.  90  and  described  below. 


202  WATERPROOFING  ENGINEERING 

Outer  vessel  or  container  for  the  glycerine  bath,  600. c.c.  Griffin 
type  Jena  beaker. 

Inner  vessel  of  air  bath,  200  c.c.  tall  lipless  Jena  beaker. 

Chair  or  support  for  inner  vessel,  cut  out  of  r^-inch  sheet 
aluminum. 

Cover  for  inner  vessel,  cut  out  of  sheet  aluminum  or  brass. 

Support  for  molds,  disc  of  brass  with  tapped  holes  for  two  or 
four  molds  suspended  on  three  hangers. 

Molds  for  shaping  bitumen. 

Commercial  glycerine;  standard  thermometer;  double  thickness 
20-mesh  iron  gauze;  iron  tripod,  stand  and  clamps;  Bunsen  or 
alcohol  burner. 

The  test  is  performed  as  follows:  One  or  more  of  the  brass  molds, 
standing  upon  a  piece  of  amalgamated  brass  or  tin,  should  be  filled 
with  the  bitumen  under  examination.  The  bitumen  may  be  softened 
by  cautiously  heating  it  in  a  small  casserole  or  tin  box  until  it  is 
sufficiently  fluid  to  be  poured  into  the  mold.  After  trimming  off 
the  upper  surface  level  with  the  mold,  place  the  sample  in  water  at 
77  deg.  Fahr.  (25  deg.  Cent.)  for  about  ten  minutes.  It  should  then 
be  suspended  in  the  air  bath  of  the  apparatus  and  the  cover  and 
thermometer  placed  in  their  proper  positions. 

The  temperature  of  the  glycerine  bath  should  also  be  77  deg. 
Fahr.  (25  deg.  Cent.)  at  the  beginning  of  the  test. 

The  apparatus  should  stand  on  double  20-mesh  iron  gauze, 
supported  on  an  iron  tripod,  and  heated  at  the  rate  of  5  deg.  Fahr. 
(2.6  deg.  Cent.)  per  minute.  The  temperature  at  which  the  sample 
of  bitumen  flows  from  the  mold  and  first  touches  the  bottom  of  the 
inner  vessel  is  recorded  as  the  melting  or  flowing  point. 

Mabery-Sieplein  Method.*  The  apparatus  consists  of  the 
following  parts: 

One  Jena  beaker,  600  c.c.  and  one  400  c.c.  capacity,  tall  forms 
without  lips. 

One  wooden  stopper  to  fit  400-c.c.  beaker;  stopper  to  have  two 
holes,  one  of  £  inch  diameter,  in  exact  center,  one  of  sufficient  size 
to  admit  thermometer  f  inch  from  center. 

One  metal  shelf,  J  by  1}  by  -^  inch  thick,  in  the  center  of  which 
and  at  right  angles  to  which  is  fastened  a  rod  of  £  inch  diameter. 

Mold  which  will  prepare  a  tablet  of  asphalt  1  by  \  by  f  inch. 

One  standard  gas-filled  thermometer  reading  to  300  deg.  Fahr. 
(149  deg.  Cent.). 

Liquid  medium  to  serve  as  bath  (such  as  anhydrous  glycerine  to 
*  Journal  American  Chemical  Society,  Vol,  23,  p.  16. 


TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING    203 


be  used  for  temperature  up  to  280  deg.  Fahr.  (138  deg.  Cent.),  linseed 
oil  above  280  deg.  Fahr.)  A  slightly  modified  apparatus  is  shown 
in  Fig.  91. 

The  400-c.c.  beaker  is  set  inside  the  600-c.c.  beaker,  and  the 
space  between  is  filled  with  the  proper  liquid  to  expand  to  approxi- 
mately within  |  inch  of  the  top  of  the  beaker  when  heated  to  280 


..Thermometer 

]  -  Strip  of  Metal 

Cork.          Rubber  Gasket 


-Oil 


MOLD 


FIG.  91. — Apparatus  for  Determining  the   Melting- point  of   Bitumen  by  the 
"  Mabery-Sieplein  "  Method. 

deg.  Fahr.  The  f-inch  rod  supporting  the  shelf  is  inserted  through 
the  central  hole  in  the  stopper  and  set  so  that  the  top  of  the  shelf  is 
exactly  1  inch  from  the  bottom  of  the  beaker.  The  thermometer 
is  inserted  in  the  other  opening  and  is  set  so  that  the  top  of  the 
bulb  is  |  inch  above  the  top  of  the  shelf  and  the  bulb  itself  is  f  inch 
from  the  rod  supporting  the  shelf. 

At  least  1  ounce  of  the  sample  to  be  examined  is  carefully  melted 
at  as  low  a  temperature  as  possible,  care  being  taken,  however,  to  see 


204  WATERPROOFING  ENGINEERING 

that  it  is  sufficiently  liquid  to  completely  fill  the  mold  and  allow  the 
escape  of  any  confined  air.  The  asphalt*  is  then  poured  into  the 
mold,  which  has  previously  been  amalgamated  by  brushing  with  a 
solution  of  nitrate  of  mercury.  When  the  asphalt  has  cooled  the 
specimen  is  removed  from  the  mold  and  placed  on  the  shelf  in 
such  a  position  that  the  longest  side  of  the  specimen  is  at  right 
angles  to  the  longest  side  of  the  shelf,  and  lies  perfectly  flat  so  that 
an  equal  amount  of  the  specimen  extends  on  either  side  beyond  the 
edge  of  the  shelf.  Care  should  of  course  be  taken  that  the  specimen 
just  touches  the  supporting  rod.  The  apparatus  is  then  heated 
gradually  by  suitable  means,  preferably  by  an  electric  oven,  allow- 
ing at  least  fifteen  minutes  for  the  temperature  to  reach  120  deg. 
Fahr.  (49  deg.  Cent.).  When  this  point  is  reached  the  temperature 
is  increased  at  the  rate  of  6  deg.  Fahr.  (3.3  deg.  Cent.)  per  minute 
until  the  portions  of  the  specimen  extending  beyond  the  sides  of  the 
shelf  have  sufficiently  softened  so  that  they  have  dropped  to  the  bot- 
tom. The  temperature  at  which  the  asphalt  just  touches  the  bottom 
of  the  beaker  is  the  melting-point. 

Richardson  or  Pellet  Method.  The  melting-point  of  bitumen 
by  the  Richardson  or  Pellet  method  is  determined  as  follows:  A 
thin  porcelain  dish,  about  2|  inches  in  diameter,  and  with  1^-inch 
sides,  filled  with  clean  mercury  to  a  distance  of  \  inch  from  the  top, 
is  placed  over  a  20-mesh  wire  gauze  and  heated  by  a  small  flame 
protected  from  draughts  by  a  chimney.  On  the  surface  of  the 
mercury  is  placed  a  thin  microscopic  cover-glass,  No.  2-0,  carrying 
the  specimen  of  asphalt  under  examination. 

When  dealing  with  hard  asphalts  that  can  be  ground  rather 
coarsely,  several  fragments,  which  will  pass  a  40-mesh  sieve  and  be 
retained  on  a  50-mesh  sieve  (about  .50  mm.  diameter),  are  spread 
on  the  glass.  This  is  then  placed  upon  the  surface  of  the  mercury, 
covered  with  a  glass  funnel,  from  which  the  stem  has  been  cut  and 
the  thermometer  passed  through  the  orifice  until  the  bulb  is  immersed 
in  the  mercury.  It  is  held  in  position  by  a  clamp  attached  to  a 
ring-stand  on  which  rests  the  dish.  Under  the  dish  a  Bunsen  burner 
is  placed  and  regulated  to  a  small  flame,  or  so  that  the  dish  is  heated 
at  the  rate  of  5.4  to  9  deg.  Fahr.  (3  to  5  deg.  Cent.)  per  minute. 
In  a  short  time  it  would  be  noticed  that  the  specimens  will  have 
changed  from  the  brown  or  brownish-black  color  of  the  powder  to 
that  more  nearly  approaching  the  original,  with  a  slight  rounding 
of  the  individual  grains.  On  further  heating,  these  globules  flow 

*  This  method  is  to  be  used  only  on  asphalt  having  a  penetration  less  than 
105  at  77  deg.  Fahr.  (25  deg.  Cent.). 


TECHNICAL  AND   PRACTICAL  TESTS  ON   WATERPROOFING    205 

together  and  form  a  thin  sheet  on  the  glass.  The  temperature  as  in- 
dicated by  the  thermometer,  at  which  the  specimen  begins  to  flow, 
is  taken  as  the  melting-point. 

Asphalts  that  cannot  be  ground  are  softened  and  pulled  out  to  a 
thread  and  cut  into  small  pieces,  about  1  c.mm.  Several  pieces 
should  be  placed  on  the  glass  together,  as  one  will  serve  as  a  check  on 
the  other,  and  thereby  lessen  the  chance  of  error.  The  softening- 
point  may  be  noted  by  the  rounding  of  the  particles  and  the  irelting- 
point  by  the  beginning  of  the  flow,  or  when  the  specimen  begins 
to  spread  out  (which  is  always  at  the  point  of  contact  with  the  glass), 
is  set  down  as  the  temperature  at  which  the  specimens  will  melt. 

General  Electric  Method.  This  method  is  quite  simple  and 
consists  of  heating  a  quantity  of  the  bitumen  to  be  tested  in  a  small 
can  until  liquid.  The  can  containing  the  liquified  bitumen  is  placed 
on  a  gram  scale  and  balanced  up.  Then  the  scale  is  set  2  grams 
back  and  enough  bitumen  is  taken  out  to  rebalance  the  scale.  The 
bitumen  is  to  be  removed  by  immersing  the  bulb  of  an  ordinary 
Fahrenheit  thermometer  about  1J  inches,  or  to  about  the  20-degree 
point.  As  the  thermometer  is  dipped  into  the  liquid  it  should  be 
turned  so  as  to  get  an  even  coating  all  over  the  surface  covered. 
Then  the  thermometer  should  be  held  horizontally  and  turned 
constantly  until  the  coating  of  bitumen  is  cooled.  Next  the  ther- 
mometer is  placed  in  a  large  test  tube,  which  in  turn  is  immersed 
in  a  beaker  filled  with  glycerine.  The  beaker  is  then  heated  over  a 
Bunsen  burner  at  the  rate  of  7.2  deg.  Fahr.  (4  deg.  Cent.)  per  minute. 
The  test  tube  should  have  a  small  amount  of  glycerine  placed  in  it. 
The  thermometer  is  run  through  a  cork  large  enough  to  support 
it  \  inch  above  the  glycerine.  The  temperature,  as  read  directly 
on  the  thermometer,  at  which  the  bitumen  drops  and  touches  the 
glycerine  is  regarded  as  the  melting-point.  Fig.  92  shows  the 
arrangement  of  the  apparatus. 

Drop  Point  and  Softening-point  of  Bituminous  Compounds.  The 
inventor  of  an  apparatus  for  determining  the  drop-point  test,  Mr. 
II.  W.  Fisher,*  says  that  his  investigation  showed:  first,  that  a  large 
majority  of  bituminous  compounds,  unlike  minerals,  have  no  well- 
defined  melting-point ;  that  what  some  chemists  specify  as  a  melting- 
point  is  really  a  softening-point  of  the  material;  and  third,  that  the 
melting-point  as  used  by  chemists  corresponds  to  the  temperature 
at  which  the  compound  will  drop;  hence,  he  believes  that  instead 
of  using  the  misnomer  "  melting-point,"  it  would  be  more  practical 
to  speak  of  the  softening-point  and  drop  point  of  compounds. 

*  Proceedings  of  American  Society  for  Testing  Materials,  Vol.  11,  1911, 


206 


WATERPROOFING  ENGINEERING 


Fig.  93  gives  a  working  drawing  of  an  apparatus  designed  to  put 
this  idea  into  practice.  For  making  the  drop-point  test,  the  com- 
pound in  placed  in  hole  2,  Fig.  93,  A,  hole  1  being  the  vent  hole. 
Hole  2  can  conveniently  be  filled  by  inverting  the  apparatus  and 
letting  the  compound  drip  from  a  heated  wire  against  which  it  is 
held.  During  this  operation  the  vent  hole  should,  of  course,  be 
filled  with  the  rod  /.  The  apparatus  and  rod  are  then  cooled, 
after  which  the  rod  is  removed.  The  surplus  compound  is  removed 
so  that  its  surface  is  flush  with  the  bottom  surface  of  the  hole. 


Thermometer 


lycerine 


Glycerine 


FIG.  92. — Apparatus  for  Finding  the  Melting-point  of  Bitumen  by  the  "  General 

Electric"  Method. 


For  making  the  softening-point  test,  the  nipple  shown  in  Fig. 
93,  (d)  is  provided.  A  wrench  for  removing  and  inserting  the  nipple 
is  shown  at  («)•  The  rod  (/)  is  placed  into  the  nipple  through  vent 
hole  4,  after  which  both  are  heated  above  the  melting-point  of  the 
compound.  The  compound  hole  3  is  then  filled,  and  after  partial 
solidification  the  rod  is  removed  and  the  surplus  compound  cut  off 
flush  with  the  top  of  the  nipple.  Afterwards,  the  nipple  is  screwed 
into  place  as  shown  at  Fig.  93  (c). 


TECHNICAL  AND    PRACTICAL   TESTS  ON   WATERPROOFING    20? 


208 


WATERPROOFING   ENGINEERING 


Heating  Coil 


For  making  the  softening-point  test  and  the  drop-point  test  in  one 
operation,  the  apparatus  is  filled  with  the  compound,  and  a  ther- 
mometer inserted  as  shown  in  Fig.  93  (c).  The  temperature  i& 
increased  at  the  rate  of  7  deg.  Fahr.  (4  deg.  Cent.)  per  minute  until 
the  compound  comes  up  through  the  mercury.  The  temperature 
at  which  this  occurs  is  called  the  softening-point  of  the  the  compound. 
Continuing  the  test  further,  the  temperature  at  which  a  drop  of  the 
compound  falls  through  the  glass  tube  is  called  the  drop  point  cf  the 
compound.  If  the  compound  has  a  high  softening-point  and  a  high 
melting-point,  a  somewhat  greater  rise  of  temperature  per  minute 

is  admissible  to  within  about  30 
deg.  Fahr.  (16.6  deg.  Cent.)  of  the 
softening-point. 

Fig.  94  illustrates  the  method 
by  which  heat  is  applied  unifcrirly 
over  the  entire  apparatus.  A  fiter 
spool  approximately  1^  inches 
inside  diameter,  3  inches  Icng, 
and  4  inches  outside  diameter,  is 
wound  with  about  240  turns  of 
No.  12  D.C.C.  magnet  wire.  By 
means  of  alternating  current  of  60 
cycles,  the  iron  testing  apparatus 
is  heated  to  any  desired  degree. 
The  voltage  employed  varies 
between  30  and  55  volts,  and  the 
current  from  4  to  8  amperes.  For 
use  with  a  direct  current  on  a  110- 
volt  circuit,  wire  of  half  the  size 

should  be  used,  and  the  voltage  could  be  varied  between  60  and  110 
volts.  By  either  method  the  temperature  can  be  kept  almost  con- 
stant at  any  degree  or  can  be  made  to  vary  as  desired. 

The  testing  apparatus  and  coil  are  placed  on  top  of  a  large  glass 
tube  which  is  embedded  in  a  wooden  base.  By  means  of  a  mirror 
at  the  side  of  the  glass  tube  in  the  base,  the  melting  of  the  compound 
in  the  drop-point  test  can  be  observed.  When  doing  this,  it  is 
necessary  to  have  an  incandescent  lamp  on  the  opposite  side  of  the 
base  from  the  mirror. 

Flow  Point  of  Bitumen.  The  flow-point  test  is  mainly  for  com- 
parison of  roofing  pitches  and  asphalts.  It  is  a  method  for  obtaining 
the  relative  flow,  or  progressive  tendency  to  glide,  of  one  asphalt 
or  pitch  with  another  accepted  as  a  standard,  under  the  following 


FIG.  94. — Electric  Apparatus  for 
Applying  Heat  Uniformly  to  the 
Apparatus  for  Determining  the 
Drop  Point  and  Softening-point 
of  Bituminous  Compounds. 


TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING    209 

condition:  On  a  corrugated  strip  of  metal  called  a  flow  plate  (Fig. 
95,  A),  8  inches  long  and  2  inches  to  4  inches  wide,  two  pills  of  equal 
volume  (made  in  a  flow  mold,  Fig.  95,  B),  one  of  each  material, 
are  placed  side  by  side  but  in  separate  grooves  on  one  end  of  the 
plate.  The  plate  is  then  placed  in  an  air  bath  with  the  loaded  end 
2J  inches  higher  than  the  other.  The  whole  is  then  placed  in  a  water 
bath  and  heated  to  the  boiling-point.  This  temperature  is  main- 
tained for  an  arbitrary  period  of  time  and  then  the  glide  of  each 
material  is  measured.  If  the  tested  material  is  longer  than  the 
standard  material,  this  indicates  that  it  is  softer;  if  the  reverse 
obtains,  that  it  is  harder. 

As  a  practical  test  the  flow  point  is  quite  serviceable  in  compar- 
ing the  relative  flow  of  roofing  pitches  and  asphalts,  but  it  is  not 
serviceable  and  in  fact  is  not  used  on  waterproofing  bitumens.  It 


B-  FLOW  MOLD 


A- FLOW  PLATES 

FIG.  95.— Mold  and  Plate  for  Flow-point  Test. 

bears  no  direct  relation  to  either  the  melting-point  or  the  penetration 
of  the  pitch  or  asphalt  tested. 

Ductility  Test  on  Bitumen.  It  is  generally  true  that  the  greater 
the  ductility  of  an  asphalt,  i.e.,  the  extent  to  which  it  is  capable  of 
being  drawn  out  in  the  form  of  a  fine  thread,  the  greater  its  cement- 
ing or  cohesive  value.  The  main  function  of  the  ductility  test, 
however,  is  to  reveal  the  possible  amount  of  healing  to  be  expected 
in  a  fractured  bitumen  in  .the  form  of  applied  waterproofing.  For 
a  given  penetration,  the  greater  the  ductility  of  an  asphalt,  the 
greater  the  healing  or  cohesive  quality.  Except  when  used  for 
joint  fillers  and  other  special  purposes,  no  asphalt  should  have  a 
ductility  less  than  20  cm.  at  77  deg.  Fahr.  (25  deg.  Cent.). 

The  test  as  made  on  the  Abraham  Tensometer*  is  shown  in 
*  Proceedings  of  American  Society  for  Testing  Materials,  Vol.  10,  1910. 


210 


WATERPROOFING  ENGINEERING 


FIG.  96.— Abraham's  Tensometer. 


TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING    211 

Fig.  96.  In  this  instrument  the  mold  is  the  most  vital  part.  In 
its  new  and  improved  form  it  consists  of  two  cylindrical  hardened 
steel  sections  (Fig.  97),  resting  together  on  circular  knife  edges  and 
maintained  in  that  position  by  three  guide  rods.  The  cross-section 
at  the  knife  edges  is  exactly  1  sq.  cm.  The  further  ends  of  these 
two  cup-like  sections  are  threaded,  and  bear  the  outer  caps  which 
serve  to  fasten  the  mold  in  the  instrument. 

After  warming  the  mold,  it  is  filled  by  unscrewing  the  upper  cap, 
bringing  the  two  sections  firmly  together  and  pouring  in  the  melted 
bituminous  substance,  which  assumes  the  form  of  a  rivet,  the  smallest 
cross-section  of  which  has  an  area  of  exactly  1  sq.  cm.  Then  it  is 


Note:  All  dimensions  in 
centimeters. 


FIG.  97. — Details  of  Mold  for  Abraham's  Tensometer. 


replaced  in  the  machine  and  drawn  apart  until  it  breaks;  the  dis- 
tance thus  traversed  being  recorded  as  the  ductility  of  the  specimen. 
Detailed  information  on  this  instrument  may  be  found  in  the  Pro- 
ceedings of  the  American  Society  for  Testing  Materials,  Vols.  10 
and  11,  1910  and  1911. 

A  simpler  and  more  commonly  used  machine,  the  "  Smith  Duc- 
tility Machine,"  is  shown  in  Fig.  98.  The  preliminary  treatment 
of  the  bitumen  and  the  preparation  of  the  briquette  for  testing  it 
with  this  machine  are  conducted  as  follows:  The  mold  is  placed 
upon  a  brass  plate.  To  prevent  the  asphalt  from  adhering  to  the 
plate  and  the  inner  side  of  the  two  removable  pieces  of  the  mold,  they 


212 


WATERPROOFING  ENGINEERING 


are  well  amalgamated.     The  different  pieces  of  the  mold  are  held 
together  in  a  clamp  or  by  means  of  an  India  rubber  band. 

The  material  to  be  tested  is  poured  into  the  mold  while  in  a 
molten  state,  a  slight  excess  being  added  to  allow  for  shrinkage  on 
cooling.  After  the  bitumen  is  nearly  cooled,  the  briquette  is 
smoothed  off  level  by  means  of  a  heated  palette  knife.  When 
cooled,  the  clamp  is  taken  off  and  the  two  center  pieces  of  the  mold 
removed,  leaving  the  briquette  of  asphalt  firmly  attached  to  the  two 
ends  of  the  mold,  which  serves  as  clips.  The  briquette  is  then 
immersed  in  water  maintained  at  77  deg.  Fahr.  (25  deg.  Cent.), 


FIG.  98. — The   "Smith,"   Direct-connected,   D.C.   Electric  Ductility   Machine 

and  Briquette  Forms. 

for  at  least  thirty  minutes,  or  until  the  whole  mass  of  bitumen  is  at 
that  temperature.  It  is  then  placed  in  the  machine  and  pulled 
apart  as  follows:  The  pointer  is  set  at  zero  on  the  centimeter  rule, 
and  a  thermometer  is  placed  through  a  cork  in  the  carriage,  which 
will  test  the  variation  in  the  temperature  of  the  water  which  may 
take  place  during  the  test.  The  distance  registered  by  the  pointer 
at  the  moment  the  thread  of  bitumen  breaks  gives  the  ductility, 
expressed  in  centimeters,  of  the  sample  under  examination. 

Evaporation  Test  on  Bitumen.  In  practice  it  is  often  necessary 
during  waterproofing  operations  to  keep  pitch  or  asphalt  for  a  long 
time  in  a  molten  condition  at  between  250  and  350  deg.  Fahr.  (121 
and  177  deg.  Cent.).  The  pitch  or  asphalt  which  will  volatilize 


TECHNICAL  AND  PRACTICAL  TESTS  ON   WATERPROOFING    213 

off  the  least  amount  of  oil  and  be  the  least  changed  in  consistency 
by  this  heating  is  the  most  desirable.  A  heating  test  is  therefore 
performed  to  determine  the  amount  of  loss  of  volatile  oil  during 
an  arbitrary  period  of  time.  This,  combined  with  the  penetration 
of  the  residue  left  after  such  heating,  is  taken  as  a  measure  of  the 
hardening  effect  to  be  expected,  due  to  aging  of  the  tar  and  bitumen 
materials.  The  reason  for  this  is  that  evaporation  and  hardening 
go  on  continuously,  though  slowly,  after  the  waterproofing  is  in 
place.  To  guard  against  rapid  hardening  and  consequent  brittleness 
of  the  bitumen,  it  is  desirable  to  use  an  asphalt  which  will  not  lose 
more  than  1  per  cent  and  a  pitch  which  will  not  lose  more  than  6 


FIG.  99. — "Frea's"  Electric  Oven.     (Chamber,  12  by  12  by  12  Inches.) 


per  cent  in  weight  when  heated  for  five  hours  at  325  deg.  Fahr. 
(163  deg.  Cent.)  in  an  electric  oven,  and  not  more  than  3  per  cent 
and  9  per  cent  respectively  in  a  gas  oven.  After  such  heating, 
neither  bitumen  shall  have  its  penetration  reduced  more  than  one- 
half  the  origind.  The  different  amounts  volatilized  in  each  oven  is 
due  to  the  relative  restricted  circulation  of  air  in  the  electric  oven. 

This  test*  is  usually  made  on  50  grams  of  bitumen  which  are 
weighed  in  a  flat-bottomed  dish,  2^  inches  inside  diameter,  and  If 
inch  deep,  placed  in  the  oven  and  held  exactly  at  325  deg.  Fahr.  (163 
deg.  Cent.)  for  five  hours.  Then  it  is  cooled  in  a  desiccator,  and  the 
loss  in  weight  is  noted.  The  electric  oven  shown  in  Fig.  99  is  some- 

*  Journal  of  Industrial  and  Engineering  Chemistry,  Vol.  3,  No.  4,  April,  1911. 


214 


WATERPROOFING  ENGINEERING 


times  used  but  gives  lower  results  than  the  gas  oven.     Therefore 
specifications  should  state  the  type  of  oven  to  be  used  for  the  test. 

The  gas  oven  shown  in  Fig.  100,  which  is  still  widely  used,  has 
the  top  and  sides  covered  with  1.8-inch  asbestos.  The  shelf  is  pro- 
vided with  a  J-inch  asbestos  pad,  large  enough  to  accommodate  the 
dishes.  The  bulb  of  a  Centigrade  thermometer  should  be  1  inch 
above  the  shelf  and  the  emergent  stem  should  show  the  90-degree 
mark.  Not  more  than  four  tests  must  be  run  in  the  oven  at  a  time. 


Thermometer' 


u 


FIG.  100. — Drying  and  Evaporating  Gas  Oven. 

1.  Chamber,  8  by  8  by  12  inches,  asbestos  covered.     2.   Dishes,  2  inches  diameter,  cen- 
trally located.     3.  Thermometer. 

Determination  of  Free  Carbon  in  Coal-tar  Pitch.  It  has  been 
stated  that  free  carbon  in  pitch  is  an  impurity  from  a  chemical 
standpoint.  This  is  not  correct,  as  the  so-called  free  carbon  content 
in  pitch  is  normally  produced  in  the  tar  itself  during  the  destructive 
distillation  of  bituminous  coal  in  gas  retorts  or  by-product  coke 
ovens.  This  free  carbon  is  present  not  as  an  impurity  but  as  a  product 
of  the  decomposition  of  hydrocarbon  vapors  during  their  travel 
along  the  heated  walls  of  the  retort  or  oven.  It  is  a  black,  organic, 
powder  held  in  suspension  by  the  tar  and  probably  consists,  not  only 


TECHNICAL  AND   PRACTICAL  TESTS  ON   WATERPROOFING    215 

of  free  carbon,  but  also  of  hydrocarbons  extremely  rich  in  carbon. 
Actual  analysis*  show  this  free  carbon  to  be  composed  of  approxi- 
mately as  follows: 

Carbon 89.85 

Hydrogen 3.30 

Nitrogen ..'...... 1 . 10 

Oxygen 3 . 13  (by  difference) 

Sulphur 1.28 

Mineral  ash 1 . 34 

The  presence  of  more  or  less  free  carbon  in  tars  is  due  to  the  heats 
at  which  the  tar  is  produced  and  the  size  and  shape  of  the  retort,  and 
the  consequent  relation  between  the  quantity  of  vapors  and  surface 
of  hot  walls  at  which  the  vapors  are  exposed.  Hence  the  production 
of  free  carbon  is  attended  by  the  production  of  other  characteristic 
hydrocarbon  compounds,  and  the  free  carbon  content  of  pitch  is 
therefore,  to  a  great  extent,  an  index  of  the  character  of  the  hydro- 
carbon in  the  bitumen.  In  general,  low  temperature  tars  contain 
smaller  amounts  of  free  carbon  and  are  characterized  by  the  presence 
of  large  amounts  of  phenol  bodies  and  sometimes  paraffin  com- 
pounds. The  tars  produced  at  higher  temperatures  containing 
more  free  carbon  also  contain  large  quantities  of  the  characteristic 
aromatic  hydrocarbons.  Therefore,  the  belief  that  pitch  can  be 
made  artificially  to  meet  certain  specifications,  after  introducing 
into  an  otherwise  pure  bitumen  an  adulterant  of  lamp  black,  or  other 
carbon,  cannot  be  substantiated,  for  such  a  mixture  would  violate 
the  requirement  of  a  straight-run  pitch,  and  in  the  second  place, 
while  the  result  produced  might  contain  the  necessary  amount  of 
free  carbon,  it  would  not  produce  the  characteristic  bitumen  accom- 
panying the  normal  free  carbon  content. 

Experience  of  years  has  even  demonstrated  that  for  certain 
purposes,  and  particularly  for  roofing  and  waterproofing  work, 
pitch,  fairly  high  in  free  carbon  (containing  between  20  and  30  per 
cent)  is  much  more  staple  and  less  susceptible  to  temperature  changes 
than  pitches  of  low  free  carbon. 

The  test  to  determine  the  free  carbon  content  of  bitumens  or, 
as  it  is  often  alluded  to,  the  hot  toluol-benzol  extraction  test,  is 
applicable  to  asphalts  and  coal-tar  pitches,  but  is  used  especially 
in  connection  with  the  latter  because  other  solvents,  such  as  carbon 
bisulphide,  are  slower  and  more  troublesome.  The  apparatus 

*  Journal  of  Industrial  and  Engineering  Chemistry,  Vol.  6,  No.  4,  April,  1914. 
Adopted  in  slightly  different  form,  in  1916,  by  the  Am.  Soc.  for  Testing  Materials. 


216 


WATERPROOFING  ENGINEERING 


for  this  test  is  shown  in  Fig.  101.  The  pitch  is  first  dried,  then  it  is 
passed  through  a  30-mesh  sieve  to  remove  any  foreign  substances. 
In  testing  materials  of  5  per  cent  or  more  insoluble  matter,  5  grams 
should  be  taken  for  the  test.  With  lesser  percentages,  10  grams 
should  be  used.  The  amount  is  weighed  in  a  100-c.c.  beaker,  and 
digested  with  about  50  c.c.  of  c.p.  toluol  on  a  steam  bath  for  a  period 
not  to  exceed  thirty  minutes.  A  filter  cup,  previously  prepared, 
is  weighed  in  the  weighing  bottle  and  placed  in  a  carbon  filter  tube 
over  a  beaker  or  flask.  The  toluol-tar  mixture  is  now  decanted 
through  the  thimble  and  washed  with  hot  c.p.  toluol  until  cleaned, 


DETAIL  SHOWING  WIRE 
SUPPORT   FOR 
FILTER  PAPER 


FIG.  101. — Extraction  Apparatus  for  Free  Carbon. 

1.  Flask.     2.  Knorr  extraction  apparatus.     3.  Copper  wire.     4.  Filter  cup  (2  sheets). 

using  some  form  of  "  policeman,"  which  is  unaffected  by  toluol, 
for  the  purpose  of  detaching  any  residue  which  may  adhere  to  the 
benker.  The  cup  is  finally  given  a  washing  with  hot  c.p.  benzol 
and  then  after  draining,  is  covered  with  a  cap  of  filter  paper  or 
alundum,  and  placed  in  the  extraction  apparatus  in  which  the  c.p. 
benzol  is  used  as  solvent.  The  extraction  is  continued  until  the 
descending  liquid  is  colorless.  The  thimble  is  then  removed,  the 
cap  taken  off,  dried  in  the  steam  oven  and  weighed  in  the  weighing 
bottle  after  cooling  in  the  desiccator.  For  more  detailed  information 
regarding  this  test,  the  reader  is  referred  to  the  "  Journal  of  Indus- 


TECHNICAL  AND   PRACTICAL  TESTS  ON   WATERPROOFING    217 

trial  and  Engineering  Chemistry,"  Vol.  3,  No.  4,  April,  1911,  and 
Vol.  6,  No.  4,  April,  1914. 

Ash  Test.  The  ash  test  is  not  of  great  significance,  and  denotes 
whether  there  has  been  a  mineral  filler  of  any  sort  added  to  the 
pitch  or  bitumen.  Normal  coal-tar  pitches  will  run  between  \  and  1 
per  cent  of  ash,  so  that  if  extraneous  matter  is  present,  the  ash 
may  run  above  this  amount.  Refined  asphalts,  except  Bermudez 
and  Trinidad  asphalt,  run  about  \  of  1  per  cent  ash. 

The  ash  determination  is  made  by  burning  to  ash  a  1-gram 
sample  of  the  material  in  a  weighed  platinum  crucible  or  dish  of 
sufficient  size.  Heat  is  gently  applied  until  the  pitch  or  bitumen 
ignites,  after  which  it  is  withdrawn.  After  the  material  ceases  to 
burn,  the  heat  is  again  applied  until  the  residue  is  burnt  free  of 
carbon.  The  crucible  and  contents  are  then  cooled  and  weighed 
and  the  ash  determined. 

Fixed  Carbon  Test.  Fixed  carbon,  as  such,  does  not  exist  in 
any  bituminous  binder,  but  is  the  amount  of  coke  produced  by 
burning  the  bitumen  in  a  certain  specified  and  generally  accepted 
manner.  The  test  is  frequently  used  in  laboratories  to  aid  in  the 
classification  of  different  bituminous  materials,  and  in  some  instances 
is  of  value  in  helping  to  determine  their  probable  origin.  Aside  from 
this,  the  test  is  of  no  value  at  all,  as  a  means  for  determining  the 
quality  of  the  material,  though  it  is  also  supposed  to  indicate  the 
mechanical  stability  and  substantial  nature  of  the  bitumen.  There 
is,  however,  little  or  nothing  in  the  fixed  carbon  test,  either  theo- 
retically or  practically,  which  shows  that  a  material  containing  over 
or  under  a  certain  definite  percentage  of  fixed  carbon  is  or  is  not 
suitable  for  waterproofing  purposes.  Because  this  is  not  a  generally 
accepted  view,  it  was  deemed  advisable  to  include  a  description  of 
this  test. 

The  test  is  conducted  as  follows:  One  gram  of  the  bituminous 
material  is  placed  in  a  platinum  weighing  crucible  between  20  and  30 
grams,  between  28  and  38  mm.  in  height,  and  having  a  tightly  fitting 
cover  provided  with  a  flange  about  4  mm.  in  depth.  The  crucible  and 
its  contents  are  then  heated,  first,  gently,  and  then  more  severely, 
until  no  smoke  or  flame  issues  between'  the  crucible  and  the  lid. 
It  is  then  placed  in  the  full  flame  of  a  Bunsen  burner  for  seven 
minutes,  holding  the  cover  down  with  the  end  of  a  pair  of  tongs 
until  the  most  volatile  products  have  been  burnt  off.  The  crucible 
is  supported  on  a  platinum  triangle  with  the  bottom  6  to  8  cm. 
above  the  top  of  the  burner.  The  flame  should  be  fully  20  cm. 
high  when  burning  free,  and  the  determination  should  be  made  in  a 


218  WATERPROOFING  ENGINEERING 

place  free  from  drafts.  The  upper  surface  of  the  cover  shall  burn 
clear,  but  the  under  surface  may  or  may  not  be  covered  with  carbon, 
depending  on  the  character  of  the  bituminous  material.  The 
crucible  is  removed  to  the  desiccator,  and,  when  cooled,  shall  be 
weighed,  after  which  the  cover  shall  be  removed  and  the  crucible 
placed  in  an  inclined  position  over  the  Bunsen  burner  and  ignited 
until  nothing  but  ash  remains.  Any  carbon  deposited  on  the  cover 
should  also  be  burnt  off.  The  weight  of  ash  remaining  should  be 
deducted  from  the  weight  of  the  residue  after  the  first  ignition  of 
the  sample.  The  resulting  weight  is  that  of  the  fixed  carbon,  which 
should  be  calculated  on  the  basis  of  the  total  weight  of  the  sample, 
exclusive  of  mineral  matter. 

.Paraffin  Test.  Paraffin  is  probably  the  best  water-resisting 
material,  but  one  of  its  adverse  properties  is  lack  of  cohesiveness. 
Therefore  its  presence  in  a  bitumen  in  more  than  moderate  quantities 
would  reduce  the  ductility  of  that  bitumen  and  also  its  adhesiveness, 
or  cementing  value.  Hence,  it  is  sometimes  desirable  to  determine 
the  amount  of  paraffin  present  and  to  limit  this  amount  depending 
upon  the  use  to  which  the  bitumen  is  to  be  put.  But  as  all  except 
paraffin  petroleums  (i.e.,  all  semi-asphaltic  and  asphaltic  petroleums) 
are  known  to  contain  less  than  6  per  cent,  of  paraffin  it  becomes 
unnecessary  for  practical  use  to  determine  the  exact  amount;  first 
because  this  amount  is  not  very  injurious,  and,  secondly,  the  duc- 
tility test  automatically  precludes  the  possible  presence  of  an  excess 
quantity  of  paraffin  in  the  asphalt.  However,  the  subject  is  believed 
to  need  further  investigation.  The  test  for  this  material  follows: 

One  hundred  grams  of  the  bituminous  material  should  be  dis- 
tilled rapidly  in  a  retort  to  a  dry  coke.  Five  grams  of  the  distillate 
should  then  be  thoroughly  mixed  in  a  60-c.c.  flask  with  25  c.c.  of 
Squibb's  absolute  ether.  Twenty-five  c.c.  of  Squibb's  absolute 
alcohol  should  then  be  added,  and  the  flask  packed  closely  in  a 
freezing  mixture  of  finely  crushed  ice  and  salt  for  at  least  thirty 
minutes.  The  precipitate  is  then  filtered  out  quickly  with  a  suction 
pump  using  a  No.  575  C.  S.  and  S.  9-cm.  hardened  standard  filter 
paper.  The  flask  and  precipitate  are  then  rinsed  and  washed  with  a 
mixture  of  equal  parts  of  Squibb's  alcohol  and  ether,  cooled  to 
1  deg.  Fahr.  (—17  deg.  Cent.),  until  free  from  oil  (50  c.c.  of  washing 
solution  is  usually  sufficient).  When  sucked  dry,  the  filter  paper 
should  be  removed  and  the  waxy  precipitate  transferred  to  a  small 
glass  disc  and  evaporated  on  a  steam  bath.  The  residue  (paraffin) 
remaining  on  the  disc  is  weighed,  and  from  this  weight  the  per- 
centage on  the  original  5-gram  sample  is  calculated. 


TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING    219 

Dimethyl  Sulphate  Test.*  'The  dimethyl  sulphate  test  is 
employed  to  detect  the  presence  of  petroleum  or  asphalt  in  coal  tar. 
It  is  used  either  to  determine  the  percentage  mixture  of  asphalt  with 
coal  tar  to  meet  certain  specifications  or  to  detect  the  presence  of 
asphaltic  products  in  coal  tar  as  an  adulterant.  The  test  is  mainly 
qualitative,  but  is  valuable  when  even  as  little  as  3  per  cent  of  pe- 
troleum or  asphalt  products  are  present  in  the  coal  tar. 

The  equipment  necessary  for  the  dimethyl  sulphate  test  is  the 
same  as  that  specified  for  the  distillation  test  recommended  by  the 
American  Society  for  Testing  Materials;  Proc.  1911,  Vol.  11,  p.  240, 
and  adopted  in  1916. 

The  pitch  specimen  is  distilled  and  fractions  taken  at  518  to  572 
deg.  Fahr.  (270  to  300  deg.  Cent.),  572  to  662  deg.  Fahr.  (300  to  350 
deg.  Cent.),  and  662  to  707  deg.  Fahr.  (350  to  375  deg.  Cent.).  These 
fractions  are  separately  stirred  and,  if  necessary,  heated  to  dissolve 
solids  which  may  be  present. 

Four  cubic  centimeters  of  distillate  from  each  fraction  are  sep- 
arately shaken  with  6  c.c.  of  dimethyl  sulphate  ((CHa^SCU)  in  a 
10-c.c.  cylinder.  After  standing  thirty  minutes  the  resultant  super- 
natant layer  of  insoluble  oil,  from  the  petroleum  or  asphalt,  is  read 
and  calculated  to  its  percentage  by  volume  of  the  sample  of  distillate 
taken.  The  results  are  reported  as  follows: 


Fractions. 

Per  Cent  of 
Distillate. 

Per  Cent  of  Distillate 
Insoluble  in  Dimethyl  . 
Sulphate. 

F. 

°C. 

518-572 
572-662 
662-707 

270-300 
300-350 
350-375 

TESTS  ON  TREATED  AND  UNTREATED  CEMENT  MORTAR  AND 

CONCRETE 

Many  tests  have  been  made  to  determine  the  permeability  of 
cement  mortars  and  concrete  with  and  without  admixtures  of  water- 
proofing materials.  It  is  well  to  understand  at  least  some  of  these. 
A  brief  description  of  the  methods  and  the  apparatus  used  and 
instructions  on  the  performance  of  these  tests  will  therefore  be  given. 
It  is  assumed  that  the  reader  is  already  acquainted  with  the  physical 
properties  and  methods  of  testing  the  constituent  materials  of  con- 
crete, and  that  he  has  a  general  knowledge  of  the  manipulation  of 
*  U.  S.  Dept.  of  Agriculture.  Bulletin  No.  314,  p.  25. 


220  WATERPROOFING  ENGINEERING 

apparatus  for  such  tests.  If  this  be  not  so,  any  standard  book  on 
concrete  may  be  consulted  with  advantage. 

Standard  Instructions  for  Permeability  Tests.  The  following 
standard  instructions  for  permeability  tests  on  mortar  waterproofed 
by  the  integral  method  have  been  used  very  successfully  in  the 
concrete  testing  laboratory  of  the  Public  Service  Commission,  First 
District,  State  of  New  York: 

"  Mix  the  mortar  in  accordance  with  the  directions  accompanying 
the  waterproofing  compound  which  is  to  be  tested.  Make  several 
specimens  to  be  tested  after  seven  days  and  several  more  to  be 
tested  after  twenty-eight  days.  In  no  case  make  fewer  than  eight 
treated  specimens  (total  number)  and  eight  untreated  specimens, 
for  comparison.  Use  extra  clean,  coarse  sand  (not  Ottawa  sand) 
for  these  specimens  in  order  that  the  waterproofing  compound  may 
receive  no  assistance  from  silt  in  the  sand. 

"  In  the  absence  of  different  directions,  mix  the  mortar  to  the 
same  consistency  as  that  of  Ottawa  sand  mortar  when  mixed  with 
60  per  cent  of  water  above  what  is  required  for  normal  consistency, 
e.g.,  if  10  per  cent  of  water  is  required  to  make  Ottawa  sand  mortar 
of  normal  consistency,  then  16  per  cent  of  water  will  be  required  to 
make  Ottawa  sand  mortar  of  the  desired  consistency.  Place  the 
mortar  in  the  7J-  or  8-inch  pipe  sections  (see  Fig.  102,  A,)  after  it 
has  been  mixed  hard  with  the  hands  for  the  time  specified,  or  until 
a  satisfactory  mixture  has  been  obtained.  Specimens  are  then 
worked  thoroughly  into  this  mold  with  hands  and  trowel.  Place  a 
small  amount  in  each  mold  and  work  it  well  to  force  out  air  bubbles 
before  adding  more  mortar.  Continue  in  this  manner  until  the 
molds  are  full.  The  iron  plates  under  the  specimens  must  be 
thoroughly  greased.  Strike  off  the  tops  of  specimens  with  a  straight 
edge. 

"  Store  the  specimens  in  moist  air  twenty-four  hours.  Then 
brush  both  surfaces  with  a  wire  brush,  mark,  and  place  them  in  water 
until  tested.  Paint  marks  must  not  be  placed  on  the  surfaces  which 
are  to  be  tested.  Specimens  are  not  to  be  removed  from  the  mold 
until  after  they  have  been  tested. 

"  Upon  removing  specimens  from  water  for  testing,  brush  both 
surfaces  again  with  a  wire  brush.  Test  under  a  pressure  of  50 
pounds  per  square  inch  for  at  least  seven  hours.  If  a  measuring 
glass  is  used,  some  means  must  be  found  to  prevent  water  from  the 
outside  from  leaking  into  the  measuring  glass,  since  it  has  a  tendency 
to  follow  down  the  outside  of  the  outlet  pipe. 

"  Record  results  at  fifteen-minute  intervals. 


TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING    221 

u  On  report  show  the  time  elapsed  from  application  of  pressure  to 
first  leakage,  the  average  leakage  for  the  time  after  specimen  began  to 
leak,  and  the  maximum  leakage  for  one  hour.  Express  results  in 
cubic  centimeters  per  square  foot  per  hour." 


B 


FIG.  102. 

A.  Permeability  Molds  and  Test  Pieces. 

B.  Permeability  Test  Piece  Holder. 

Description  of  Standard  Apparatus.  The  apparatus*  for  holding 
the  test  pieces  is  shown  in  Fig.  102,  B,  in  sections  ready  to  assemble. 
Fig.  103  is  a  cross-sectional  view  of  the  test  piece  assembled  ready 
for  testing.  A ,  A  are  rubber  washers  of  5-inch  inside  diameter  and 
8-inch  outside  diameter;  B,  B  are  cast-iron  top  and  bottom  sections 

*  Technologic  Paper  No.  3,  U.  S.  Bureau  of  Standards,  Dept.  of  Commerce 
and  Labor, 


222 


WATERPROOFING   ENGINEERING 


of  the  holder;  C  is  the  test  piece  7J  inches  in  diameter  and  1,  2  or  3 
inches  thick  and  is  retained  in  corresponding  short-length  sections 
of  7^-inch  diameter  wrought-iron  pipe;  D  is  the  retainer  in  which 
the  water  passing  through  the  test  piece  is  caught. 

The  foregoing  directions  and  apparatus  have  become  most 
generally  used  in  laboratory  practice.  Other  methods  are  employed 
but  the  basic  principles  remain  the  same,  that  is,  the  measurement 
of  the  quantity  of  water  that  will  come  through  mortar  or  concrete 
under  a  given  static  head  of  water.  One  of  these  methods  used  by 
Mr.  Francis  M.  McCullough,  B.S.,  in  testing  the  permeability  of 


FIG.  103. — Cross-section  of  Apparatus  for  Holding  Permeability  Test  Pieces. 

waterproofed  concrete  at  the  University  of  Wisconsin,*  is  exemplary 
and  the  following  is  a  description. 

Method  of  Testing  Permeability  of  Waterproofed  Concrete. 
The  apparatus  used  by  Mr.  McCullough  for  testing  the  permeability 
of  concrete  consists  essentially  of  eight  6-inch  pipes  filled  with  con- 
crete and  a  pipe  system  connected  with  air  and  water  reservoirs. 
Fig.  104,  A,  shows  in  detail  the  mold  and  attached  casting  and  Fig. 
104,  B,  is  a  general  drawing  of  the  pipe  system  for  four  specimens, 
the  apparatus  for  the  remaining  four  specimens  being  the  same  as 
shown. 

*  Bulletin  No.  336,  University  of  Wisconsin. 


TECHNICAL  AND   PRACTICAL  TESTS  ON  WATERPROOFING    223 


The  molds  are  6-inch  wrought-iron  pipe,  12 \  inches  long,  with 
a  cast-iron  flange  screwed  to  the  upper  end.  In  order  to  prevent 
the  passage  of  water  between  the  pipe  and  the  cement  lining  ten 
or  twelve  V-shaped  grooves  were  cut  in  each  pipe,  each  groove 
extending  around  the  inner  surface  of  the  pipe. 

This  flanged  pipe  was  attached  to  the  casting  by  means  of  six 
eyebolts.  A  f-inch  pipe,  4  feet  6  inches  long,  was  screwed  into  this 
casting.  Each  of  these  f-inch  pipes  was  jointed  to  the  main  pipe, 
which,  in  turn,  connected  with  the  water  main  and  with  the  air 
reservoirs.  The  shut-off  globe  valves  for  water  and  air  are  shown 
on  the  pipes  connecting  the  main  pipe  with  the  water  main  and  with 


Water  Main  Connected  with  University  Supply 

Water  Valve 

-AirVaWA" 


Pipe  Connecting 
with  Air  Tank 


FIG.  104. 

A.  Apparatus  for  Testing  Permeability  of  Concrete. 

B.  Section  of  Mold  and  Casting. 

the  air  reservoirs.  The  cast-iron  cylinders,  6J  inches  in  diameter  and 
4  feet  8  inches  long,  formed  the  air  reservoirs.  They  were  connected 
with  a  large  air  tank,  not  shown,  by  means  of  the  pipe  shown  in 
Fig.  104,  B,  a  shut-off  globe  valve  being  placed  between  the  air  tank 
and  air  reservoirs. 

A  glass  tube  and  attached  scale  graduated  to  hundredths  of  a 
foot  were  fastened  to  each  f-inch  pipe  in  order  to  obtain  the  water 
level  in  the  pipe.  The  globe  valve  V  was  used  in  order  to  dis- 
connect any  specimen  proving  defective.  The  f-inch  pipe  and  glass 
tube  were  drained  by  means  of  the  needle  valve.  A  gauge  registered 
the  air  pressure. 


224  WATERPROOFING  ENGINEERING 

The  specimens  were  securely  bolted  to  the  castings,  a  rubber 
gasket  being  used  between  the  finished  faces  of  flange  and  casting. 
With  the  air  valve  A  closed  and  the  air  valve  B  opened,  air  was 
admitted  to  the  reservoirs  until  sufficient  pressure  was  obtained. 
The  water  valve  was  opened  and  water  was  allowed  to  fill  the  f-inch 
tubes.  Care  was  taken  that  the  pressure  did  not  exceed  that  used  in 
the  test,  this  being  regulated  by  opening  the  needle  valves.  Air 
valve  B  was  closed  and  air  valve  A  connecting  with  the  air  reser- 
voirs was  opened,  thus  subjecting  the  specimens  to  pressure. 

The  rate  of  flow  of  the  water  through  the  concrete  was  obtained 
by  noting  the  scale  readings  and  the  time.  Pressures  were  also 
noted,  but  they  showed  very  little  decrease  as  the  volume  of  the 
air  reservoirs  was  very  large  compared  to  the  volume  of  the  f-inch 
pipes.  No  readings  were  taken  for  five  minutes  after  the  pressure 
was  on.  As  the  rate  of  flow  rapidly  decreased  readings  were  taken  at 
intervals  of  ten  or  fifteen  minutes  for  the  first  few  hours  and  then  at 
intervals  gradually  increasing  from  two  to  eight  hours.  The  bottoms 
of  the  specimens  were  frequently  examined  and  any  dampness  noted. 

When  readings  are  taken  all  joints  should  be  carefully  examined 
and  any  leaks  noted,  and  the  effect  of  this  leakage  eliminated  as  much 
as  possible  in  reducing  the  data. 

The  proportions  by  volume  of  the  concrete  were  1:3:5,  the 
required  amount  of  materials  being  weighed.  No  attempt  was  made 
to  secure  a  waterproof  concrete  by  proper  proportioning.  On  the 
contrary,  a  lean  mixture  was  desirable  in  order  to  bring  out  the  water- 
proofing qualities  of  the  compounds.  Local  stone  and  sand  and 
Portland  cement  were  used.  The  stone  was  a  rather  sandy  lime- 
stone, while  the  sand  was  of  the  fine  .bank  variety. 

Results  of  Permeability  Tests  on  Waterproofed  Concrete.  We 
will  now  consider  the  results  of  these  tests  on  concrete  treated  with 
a  few  waterproofing  compounds.  These  compounds  may  be  classi- 
fied according  to  the  manner  in  which  they  were  used  in  the  tests. 

(1)  Compounds  applied  to  the  surface  of  the  concrete,  which  in 
themselves  may  be  sub-divided  into  three  classes : 

(a)  Compounds  which  are  applied  as  surface  paints. 

(b)  Compounds   which   were   applied   in   layers   to   form   a 

membrane. 

(c)  Compounds  which  were  applied  as  a  surface  coating  in  the 

form  of  a  thick  layer. 

(2)  Foreign  ingredients  added  to  the  body  of  the  concrete. 

(3)  Foreign  ingredients  added  to  the  mortar  coating. 

(4)  Plain  cement  mortar. 


TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING    225 


Different  methods,  as  illustrated  in  Fig.  105,  were  used  in 
finishing  the  upper  surface  of  the  specimens,  depending  upon  the  kind 
of  waterproofing  compound  used.  As  shown  in  Fig.  105,  A  and  B, 
the  concrete  was  finished  flush  with  the  top  of  the  pipe,  the  upper 
surface  of  the  concrete  being  well  troweled.  Before  troweling,  the 
specimens  were  allowed  to  stand  a  half  hour  in  order  that  the  free 
water  on  the  concrete  might  be  absorbed.  The  cement  lining  extends 
to  the  top  of  the  concrete  in  B,  while  in  A  it  is  cut  off  \  inch  below. 
In  the  specimens  that  were  coated  with  mortar,  as  shown  in  Fig.  105, 
C  and  D,  the  surface  of  the  concrete  was  f  inch  below  the  top  of  the 


Waterproofing  Material 


Material 


Mortar  Coating  for 
NWaterproofing 


Mortar  Coating  for 
Waterproofing/ 


C  D 

FIG.  105.— Methods  of  Finishing  Upper  Surface  of  Concrete  Specimens. 

pipe.  After  the  concrete  had  absorbed  the  standing  water  the 
mortar  top  was  added,  the  surface  of  the  concrete  and  the  mortar 
being  thoroughly  troweled.  In  applying  all  surface  preparations, 
care  was  taken  to  secure  a  dry,  clean  surface  and  to  have  the  prep- 
aration well  brushed  in.  The  water  pressure  varied  from  20 
pounds  to  40  pounds  per  square  inch  applied  continuously  from 
three  to  seven  days. 

In  all  cases  except  those  in  which  the  compounds  were  applied 
in  the  form  of  a  membrane,  the  results  were  variable.  The  materials 
used  were  more  or  less  reliable  but  the  results  obtained  were  not 
often  enough  satisfactory  to  establish  a  single  superior  compound. 


WATERPROOFING   ENGINEERING 


In  most  cases  where  a  material  withstood  the  low  pressure  it  failed 
completely  under  the  higher  pressure.  None  withstood  either 
pressure  absolutely  without  absorption  or  percolation,  with  the 


^  Bolt* 


SECTION  ON  B-B 


-U<  Tubing 

,%"</>  BolU 


PUL  SPECIMEN 


On  No.  8-12 


PUHC  SPECIMEN 

FIG.  106. — Types  of  Permeability  Specimens. 

one  exception  noted  above.  Similar  tests  made  on  f-inch  plain 
cement  mortar  of  proportions  1  :  1J  applied  to  the  concrete  (Fig. 
105,  C),  proved  two  facts:  (1)  that  plain  mortar  can  be  made  rea- 


TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING  227 

sonably  watertight;  (2)  that  some  of  the  above  compounds,  such 
as  the  foreign  ingredients  added  to  the  mortar  coating,  are  also 
reasonably  effective  and  warrant  their  use  under  certain  conditions. 
Results  of  Permeability  Tests  on  Plain  Concrete.  Still  another 
method  for  testing  the  permeability  of  mortar  and  concrete,  though 
only  occasionally  used,  is  worth  noting.  In  an  elaborate  series  of 
permeability  tests,*  in  which  machine-mixed  concrete  and  large 
specimens  having  a  prescribed  volume  of  concrete  were  used  without 


FIG.  107.— Longitudinal  Sections  of  "PU"  and  "PUHC"  Permeability  Specimens. 

any  waterproofing  added  to  them,  many  valuable  facts  are  made 
patent.  The  forms  of  specimens  are  shown  in  Figs.  106  and  107. 
In  molding  these  test  pieces,  both  mortar  shell  and  concrete  core 
were  cast  at  the  same  time.  The  area  of  the  core  is  1  square  foot, 
hence  the  leakages  read  were  in  terms  of  this  unit. 

The  results  of  these  permeability  tests,  made  on  294  gravel- 
concrete  specimens,  agree  very  well  with  similar  tests  made  by 
other  experimenters.  Of  the  above  number  88  were  of  1  :  1^  :  3 
and  67  of  1:2:4  proportions  by  volume;  98  were  of  1:3:9 
proportions  by  weight. 

*  Journal  of  the  Western  Society  of  Engineers,  November,  1914,  Vol.  19,  No.  9. 


228  WATERPROOFING  ENGINEERING 

None  of  the  coricretes  tested  was  absolutely  watertight  if  we 
consider  continuous  flow  into  the  specimen  as  proof  of  permeability, 
but  the  majority  of  mixes  were  so  impervious  that  no  visible  evidence 
of  flow  appeared.  For  most  purposes  such  mixes  can  be  considered 
watertight. 

The  visibility  of  dampness  on  the  bottom  of  the  specimens 
increased  with  the  humidity  of  the  air  and  the  non-homogeneity  of 
the  concrete.  The  minimum  rate  of  flow  for  which  leakage  was  indi- 
cated was  0.00011  gallon  (approximately  .42  c.c.)  per  square  foot 
per  hour. 

In  tests  of  nearly  all  of  the  properly  made  mixes  of  1  :  2|  :  4J 
proportions,  or  richer,  the  rate  of  flow  for  a  fifty-hour  period  was  less 
than  0.0001  gallon  (approximately  .38  c.c.)  per  square  foot  per  hour 
under  a  pressure  of  40  pounds  per  square  inch. 

Through  increasing  the  fineness  of  the  cement  a  reduction  in 
the  rate  of  flow  and  a  considerable  increase  in  the  strength  of  a 
1:3:6  mix  were  secured. 

By  grading  the  sand  and  gravel  in  accordance  with  Fuller's 
curve  it  was  possible  to  obtain  practically  watertight  concrete  of 
1:3:6  proportions  under  pressures  less  than  40  pounds  per  square 
inch.  To  secure  such  results,  however,  requires  great  care  and 
careful  supervision  in  mixing,  in  determining  the  proper  consistency, 
in  placing,  and  in  curing  the  concrete. 

In  the  proportioning  of  such  materials  as  these,  volumetric 
analysis  coupled  with  a  determination  of  the  density  and  air  voids 
yields  very  valuable  information  concerning  the  best  proportions  of 
sand  and  gravel  for  a  given  proportion  of  cement.  If  proportions 
must  be  selected  arbitrarily,  a  1  :  1J  :  3  mix,  by  volume,  is  very 
impervious.  It  should  be  remembered,  however,  that  the  volume 
changes  in  rich  mixtures  due  to  alternate  wetting  and  drying  are 
much  greater  than  for  lean  mixtures.  Consequently  due  attention 
must  be  given  to  the  provision  of  expansion  joints  and  reinforce- 
ment in  structures  made  of  rich  mixtures. 

The  use  of  the  proper  amount  of  water  necessary  to  produce 
a  medium  or  mushy  consistency  is  one  of  the  most  important  con- 
ditions in  securing  impervious  concrete,  especially  when  lean  mix- 
tures are  used.  Dry  mixtures  cannot  be  sufficiently  compacted  in 
the  molds  and  are  more  difficult  to  cure  properly  than  the  mushy 
mixtures.  Although  the  use  of  a  wet  consistency  does  not  materially 
affect  the  imperviousness  of  very  rich  mixes,  such  as  1  :  1J  :  3,  it 
greatly  increases  the  flow  through  a  lean  mix. 

For  lean  mixes  made  from  damp  sand,  it  seems  advisable  to  mix 


TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING    233 


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234  WATERPROOFING  ENGINEERING 

of  a  cement  floor  are  almost  directly  proportional  to  the  amount  of 
troweling  work  put  upon  it  without  crazing  the  surface. 

From  a  study  of  numerous  applications,  of  mineral,  metal,  and 
liquid  floor  hardeners,  and  a  review  of  Table  X,  the  liquids,  in 
general,  seem  to  give  much  better  service,  being  also  more  easily 
applied,  and  when  wear  develops,  may  be  as  easily  reapplied. 

The  abrasion  tests,*  results  of  which  are  given  in  Table  X, 
were  made  on  an  abrasion  apparatus  consisting  of  a  16-inch  cast- 
iron  disc,  revolving  at  the  rate  of  42  revolutions  per  minute.  Fine 
sand  was  fed  upon  this  disc  by  means  of  two  funnels  each  placed 
6  inches  from  the  center  of  the  disc.  The  size  of  the  opening  at 
the  bottom  of  each  funnel  was  regulated  by  means  of  a  metal  slide. 
The  sand  used  was  fine  beach  sand  graded  so  that  all  particles 
passed  a  No.  50  sieve  and  were  retained  on  a  No.  100  sieve.  Two 
test  samples  placed  opposite  each  other,  were  held  down  upon  this 
disc  by  being  placed  in  weighted  cylindrical  holders.  This  machine 
was  so  devised  that  these  holders  could  hold  the  center  of  the  speci- 
mens always  on  the  circumference  of  a  12-inch  circle. 

Mortar  cylinders  2  inches  in  diameter  and  1|  inches  high  were 
used  as  test  samples.  A  good  grade  of  Portland  cement  and  Long 
Island  bank  sand  were  used  throughout.  No  attempt  was  made  to 
surface  a  sample  with  a  thin  coating  of  any  compound.  Wherever 
specific  directions  were  furnished  with  a  compound,  these  directions 
were  closely  adhered  to.  Eight  cylinders  were  made  with  each 
batch  of  mortar  to  be  tested,  four  cylinders  containing  the  com- 
pound to  be  tested  and  the  remaining  four  were  of  plain  mortar. 
Two  treated  and  two  untreated  specimens  were  tested  at  seven 
days  and  the  remaining  specimens  were  tested  at  twenty-eight  days. 

All  specimens  were  dried  until  they  showed  no  further  loss  in 
weight.  The  specimens  were  then  carefully  weighed  and  calipered. 
Measurements  were  taken  by  micrometer  calipers  at  five  points — 
the  center  and  at  four  points  equally  distant  on  the  circumference. 
The  cylinders  were  ground  in  groups  of  two — one  plain  and  one 
treated  specimen — for  thirty  minutes.  Approximately  450  grams 
of  sand  were  used  in  each  test.  The  samples  were  then  again 
weighed  and  calipered.  In  determining  the  loss  in  thickness  of  each 
cylinder,  the  cylinder  was  considered  as  being  composed  of  four 
triangles,  the  center  being  the  common  vertex.  For  this  reason, 
the  center  measurement  was  given  a  weight  of  four  and  each  mea- 
surement on  the  circumference  given  a  weight  of  two. 

*  Tests  made  in  Physical  Laboratory  of  the  Public  Service  Commission,  1st 
Dist.,  New  York,  1917. 


TECHNICAL  AND  PRACTICAL  TESTS  ON   WATERPROOFING    231 

The  results  noted  in  the  table  are  undoubtedly  representative  of 
average  1:2:4  concrete. 

The  most  interesting  fact  disclosed  is  that  the  absorption  of  con- 
crete is  very  little  affected  by  the  greater  or  less  absorptiveness  of 
the  various  large  aggregates  except  cinders  (see  Table  I).  In  other 
words  the  absorption  of  concrete  is  dependent  mainly  on  the  matrix. 


TEST  ON  CONCRETE  FLOOR  HARDENERS 

Concrete  floor  hardeners  are  applied  to  floors  for  the  purpose  of 
making  them  dustproof  and  waterproof  by  surface  densification. 
The  term  "  floor  hardener  "  is  a  misnomer,  as  most  of  the  materials 
used,  with  the  exception  of  carborundum  and  like  materials,  do  not 
add  to  the  hardness  of  the  floor,  but  give  merely  a  better  wearing 
floor  due  to  other  properties  than  hardening  properties.  Abrasive 
tests  described  below  on  these  materials  conclusively  prove  the  fact 
that  they  do  not  add  hardness  to  a  cement  floor.  However,  these 
materials  are  not  confined  to  minerals  or  metals  only,  but  may  be 
liquids,  with  bases  of  wax,  oil,  varnish,  etc.,  these  generally  being 
applied  to  the  finished  floor.  The  mineral  or  metal  materials  are 
sometimes  incorporated  in  the  concrete  or  cement  mortar  before 
these  have  finally  set,  but  in  most  instances,  they  are  merely  dusted 
on  the  surface  and  troweled  in.  This  gives  a  floor  surface  with  a 
more  or  less  thin  layer  which  may  wear  through,  leaving  the  floor 
practically  in  the  same  condition  as  an  untreated  cement  floor. 
The  effect  of  the  more  successful  floor  hardeners  is  to  produce  a 
floor  really  more  dust  proof,  due  to  the  smooth  surface  of  the  finished 
floor.  This  naturally  implies  a  floor  with  a  minimum  of  surface 
voids  and  crevices  to  hold  dust  and  moisture,  and  also  little  liability 
to  raveling.  However,  when  a  hard  material  like  carborundum 
is  used,  a  hard  floor  and  not  a  smooth  floor  is  obtained.  This  type  of 
floor  presents  a  rough,  coarse  surface,  and  is  in  fact  a  very  dusty  one. 
From  the  point  of  view  of  floor  hardeners,  the  best  dustproof  floor 
is  a  terrazzo  floor  (mainly  used  in  public  buildings),  in  which  the 
wearing  surface  is  largely  the  coarse  aggregate  used  in  the  floor. 
This  is  ground  by  hand  or  by  machine  to  present  a  maximum  wear- 
ing surface  and  reduce  the  mortar  of  the  wearing  surface  to  a 
minimum. 

The  efficiency  of  some  of  the  floor  hardeners  is  often  less  due  to 
the  character  of  the  hardener  than  to  the  extra  work  required  in 
troweling  the  treated  floor.  In  fact,  the  smoothness  and  hardness 


232 


WATERPROOFING  ENGINEERING 


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234  WATERPROOFING  ENGINEERING 

of  a  cement  floor  are  almost  directly  proportional  to  the  amount  of 
troweling  work  put  upon  it  without  crazing  the  surface. 

From  a  study  of  numerous  applications,  of  mineral,  metal,  and 
liquid  floor  hardeners,  and  a  review  of  Table  X,  the  liquids,  in 
general,  seem  to  give  much  better  service,  being  also  more  easily 
applied,  and  when  wear  develops,  may  be  as  easily  reapplied. 

The  abrasion  tests,*  results  of  which  are  given  in  Table  X, 
were  made  on  an  abrasion  apparatus  consisting  of  a  16-inch  cast- 
iron  disc,  revolving  at  the  rate  of  42  revolutions  per  minute.  Fine 
sand  was  fed  upon  this  disc  by  means  of  two  funnels  each  placed 
6  inches  from  the  center  of  the  disc.  The  size  of  the  opening  at 
the  bottom  of  each  funnel  was  regulated  by  means  of  a  metal  slide. 
The  sand  used  was  fine  beach  sand  graded  so  that  all  particles 
passed  a  No.  50  sieve  and  were  retained  on  a  No.  100  sieve.  Two 
test  samples  placed  opposite  each  other,  were  held  down  upon  this 
disc  by  being  placed  in  weighted  cylindrical  holders.  This  machine 
was  so  devised  that  these  holders  could  hold  the  center  of  the  speci- 
mens always  on  the  circumference  of  a  12-inch  circle. 

Mortar  cylinders  2  inches  in  diameter  and  1J  inches  high  were 
used  as  test  samples.  A  good  grade  of  Portland  cement  and  Long 
Island  bank  sand  were  used  throughout.  No  attempt  was  made  to 
surface  a  sample  with  a  thin  coating  of  any  compound.  Wherever 
specific  directions  were  furnished  with  a  compound,  these  directions 
were  closely  adhered  to.  Eight  cylinders  were  made  with  each 
batch  of  mortar  to  be  tested,  four  cylinders  containing  the  com- 
pound to  be  tested  and  the  remaining  four  were  of  plain  mortar. 
Two  treated  and  two  untreated,  specimens  were  tested  at  seven 
days  and  the  remaining  specimens  were  tested  at  twenty-eight  days. 

All  specimens  were  dried  until  they  showed  no  further  loss  in 
weight.  The  specimens  were  then  carefully  weighed  and  calipered. 
Measurements  were  taken  by  micrometer  calipers  at  five  points — 
the  center  and  at  four  points  equally  distant  on  the  circumference. 
The  cylinders  were  ground  in  groups  of  two — one  plain  and  one 
treated  specimen — for  thirty  minutes.  Approximately  450  grams 
of  sand  were  used  in  each  test.  The  samples  were  then  again 
weighed  and  calipered.  In  determining  the  loss  in  thickness  of  each 
cylinder,  the  cylinder  was  considered  as  being  composed  of  four 
triangles,  the  center  being  (he  common  vertex.  For  this  reason, 
the  center  measurement  was  given  a  weight  of  four  and  each  mea- 
surement on  the  circumference  given  a  weight  of  two. 

*  Tests  made  in  Physical  Laboratory  of  the  Public  Service  Commission,  1st 
Dist.,  New  York,  1917. 


TECHNICAL  AND   PRACTICAL  TESTS  ON   WATERPROOFING     235 

From  a  detailed  review  of  Table  X  the  following  facts  are 
noted:  Iron  filings  injure  the  wearing  qualities  of  a  concrete  floor. 
Iron  filings  treated  with  salammoniac  cause  a  mortar  to  fail 
completely.  These  results,  however,  are  not  regarded  as  conclusive. 

A  4  per  cent  solution  of  calcium  chloride  will  rapidly  increase 
the  hardness  and  tensile  strength  of  a  mortar  during  the  first  seven 
days.  This  advantage  however  is  overcome  after  twenty-eight  days. 

Carborundum  greatly  increases  the  hardness  of  a  floor.  Very 
little  wear  occurs  after  the  top  skin  of  cement  has  been  ground  off. 

A  coarse  sand  aggregate  or  an  aggregate  of  sand  and  grits  gives  a 
more  wear-resistant  mortar  than  that  made  of  finer  sand. 

Comparison  of  Melting-points  of  Bitumens.*  Ten  samples  of 
asphalt  were  tested  according  to  the  requirements  of  each  of  the 
first  three  of  the  following  standard  methods  for  finding  the  melting- 
point  of  bituminous  material  and  twenty  samples  according  to  the 
fourth  method  (but  not  tabulated  below). 

(1)  C.  I.  Robinson,  or  the  Ring  and  Ball  Method.     (R.  and  B. 
Method). 

(2)  Cube-in-water  Method  (C.-in-W.  Method). 

(3)  Kraemer  and  Sarnow  Method  (K.  and  S.  Method). 

(4)  Mabery-Sieplein  Method  (M.-S.  Method). 

A  careful  perusal  of  the  description  of  these  methods,  given  on 
page  197  will  facilitate  understanding  the  purpose  and  results  of  this 
test,  especially  because  of  lack  of  uniformity  of  opinion  by  chemists 
as  to  preference,  superiority  or  correctness  of  any  of  them. 

From  the  values  in  Table  XI  it  is  evident  that  the  Cube-in-water 
Method  registers  a  comparatively  high  melting-point  and  cannot 
be  altogether  reliable  for  the  reason  that  the  specific  gravity  of  the 
bitumen  enters  as  a  factor  in  these  figures.  It  is  also  evident  that 
the  Ring  and  Ball  and  Kraemer  and  Sarnow  Methods  are  probably 
more  correct,  because  of  close  agreement  of  the  results  and  because 
these  are  independent  of  the  specific  gravity  of  the  bitumen. 

A  similar  but  more  extended  series  of  tests  f  was  made  on  various 
asphalts  and  pitches,  to  determine  the  conversion  factors  between 

*  This  and  the  following  eighteen  tests  are  reprinted  from  a  paper  by  the 
author  in  the  N.  Y.  Municipal  Engineers'  Journal,  Vol.  3,  No.  7,  September,  1917. 
Attention  is  directed  here  to  the  fact  that  the  following  tests  are  far  from  being 
exhaustive  or  complete  either  in  technique  or  interpretation  of  results.  But 
partly  for  the  reason  explained  in  the  forepart  of  this  chapter  and  partly  because 
of  their  suggestive  value  it  was  considered  warrentable  to  reprint  them  here. 

f  These  tests  were  made  in  the  Chemical  Laboratory  of  the  Public  Service 
Commission  for  the  First  District,  State  of  N.  Y.;  R.  L.  Oberholser,  Chief 
Chemist. 


236 


WATERPROOFING  ENGINEERING 


the  four  methods.  From  the  results  thus  obtained,  and  the  tabu- 
lated values  given  above,  Table  XII  was  constructed.  By  means 
of  this  table  the  known  melting  point  of  a  bitumen  by  one  method 
is  readily  converted  to  an  equivalent  value  by  another  method. 

TABLE  XL— COMPARATIVE    MELTING-POINTS   OF   BITUMEN 


Asphalt 
Sample, 
Number. 

Ball-and-ring 
Method, 
Degrees 
Fahrenheit. 

Difference 
Between 
Ball-and-ring 
and  Cube-in 
Water 
Methods. 

Cube-in- 
Water 
Method, 
Degrees 
Fahrenheit. 

Difference 
Between 
Cube-in- 
Water  and 
Kraemer  and 
Sarnow 
Methods. 

Kraemer  and 
Sarnow 
Method, 
Degrees 
Fahrenheit. 

1  

169 

31 

200 

33 

167 

2..  
3  

109 
151 

30 

27 

139 

178 

37 

29 

102 
149 

4  

129 

24 

153 

32 

121 

5  

122 

30 

152 

33 

119 

6.    . 

124 

26 

150 

30 

120 

7  
8  

134 
131 

25 
29 

159 
160 

33 

40 

126 
120 

9  

127 

31 

158 

32 

126 

10  

139 

27 

166 

37 

129 

TABLE  XII.— CONVERSION  OF   MELTING-POINTS  OF  BITUMEN 


Method      Given  —  Values 
in  Degrees  Fahrenheit. 

To  TRANSFORM  TO 

Ball-and-ring 
Method. 

Kraemer 
and  Sarnow 
Method. 

Mabery- 
Sieplein 
Method. 

Cube-in- 
Water 
Method. 

Ball-and-ring 

Add    5 

Add  25 
Add  35 

Subtract  20 
Subtract  25 

Subtract  30 
Subtract  35 
Subtract  15 

Kraemer  and  Sarnow  .  . 
Mabery-Sieplein  
Cube-in-water  

Subtract  5 
Add  20 
Add  30 

AddlS 

Effect  of  Heat  on  Various  Pitches  Mixed  with  Linseed  Oil.*  A 
mixture  of  pitch  and  linseed  oil  is  often  used  as  a  pipe-coating, 
and  as  a  coating  for  steel  and  cast-iron  tunnel  segments.  In  applying 
this  compound,  it  is  found  necessary  to  heat  it  in  open  tanks  IGI  very 
long  periods.  Hence,  the  question:  what  effect  has  such  heating 
upon  the  mixture?  To  learn  the  answer  to  this  question,  a  seventy- 
two  hour  heating  test  was  made  with  three  grades  of  pitch,  the 
results  of  which  are  given  in  Table  XIII. 

*  Test  made  in  Chemical  Laboratory  of  Public  Service  Commission  for 
the  First  District,  State  of  N.  Y.;  R.  F.  Oberholser,  Chief  Chemist. 


TECHNICAL  AND  PRACTICAL  TESTS  ON   WATERPROOFING    237 


TABLE  XIII.— EFFECT  OF  HEAT  ON  MIXTURES  OF  COAL-TAR 
PITCH  AND   LINSEED  OIL 


PITCH  PRIOR  TO  HEATING. 

AFTER  24  HOURS  HEATING. 

& 

•8 

*T» 

| 

|{ 

6 

c 

1 

.. 

M 

q 

Kind  of  Pitch. 

(3.1 

ftj 

"S'sj 

*j  05 

PH 

-o% 

I 

|^ 

1 

•§fc 

Bfe 
fl 

1 

w| 

llj 

•2  Six 

IB! 

ijQo 

6? 

Sc3 

*S  of^ 

IB! 

III 

Sa 
U  a 

Sc3 

03   <D 

PH 

i 

3 

£ 

02 

S 

£ 

* 

Soft 

5 
None 

76 

107 

29.5 

84 
94 

108 
120 

29.9 
30.9 

3.80 
3.36 

Medium    | 

5 
None 

90 

123 

29.9 

104 
106 

136 
138 

30.9 
30.8 

5.99 
3.08 

Hard          { 

5 
None 

110 

120 
135 

152 
172 

31.3 
32.1 

2.70 
4.09 

144 

29.6 

AFTER  48  HOURS  HEATING. 

AFTER  72  HOURS  HEATING. 

g 

i 

c 

M 

i 

I 

£ 

£ 

S3 

q 

Kind  of  Pitch. 

il 

+j"c8 

~C3 

^  e3 

S 

8 

15 

'3  <a 

d 

Is 

5,8 

_O 

(-   O> 

1     o 

£S      CJ 

^ 

|M   CD 

.s  &L 

&0  £ 

^X 

c  £  . 

M    "^v 

•a 

^sO 

lef 

IB! 

^s 

Jfe 

'S  «^ 

5BI 

2O'S 

«^J3 

°l 

gg 

eg 

* 

fe  . 

i 

1 

H 

Soft            [ 

92 
106 

118 
132 

33.4 
31.5 

5.79 
6.55 

102 
117 

138 
150 

31.5 
34.3 

9.22 
10.10 

Medium    < 

121 
130 

154 
162 

31.4 
33.6 

8.34 
44.4 

145 
138 

180 
170 

32.9 
35.4 

11.50 

4.97 

Hard 

136 

154 

178 
194 

32.7 

34.9 

3.24 

7.47 

150 
168 

188 
208 

33.5 
36.3 

5.68 
10.85 

Straight-run  coal-tar  pitch  and  raw  linseed  oil  of  good  quality 
were  used  in  this  test.  The  melting-point  was  determined  by  the 
Cube-in- water  Method. 

This  test  discloses  the  fact  that  prolonged  heating  of  pitch  even 
when  mixed  with  linseed  oil,  is  injurious,  as  shown  by  the  amount 
of  oil  evaporated,  and  the  great  rise  in  melting-point. 

Hence  it  is  imperative  not  to  subject  this  coating  material  to 
continuous  heat,  but  if  this  becomes  unavoidable,  the  tank  must  be 
frequently  replenished  with  new  material. 


238  WATERPROOFING   ENGINEERING 

Flowing  and  Bonding  Properties  of  Pitch  Containing  Small 
Quantities  of  Asphalt  or  Linseed  Oil.  To  obviate  the  danger  and 
nuisance  of  using  hot  coal-tar  pitch  for  waterproofing  by  the  mem- 
brane method  under  compressed  air,  tests  were  made  to  determine 
the  flowing  and  bonding  properties  of  different  melting-point  pitches 
mixed  with  either  5  per  cent  of  raw  linseed  oil  or  5  per  cent  of  dif- 
ferent melting-point  asphalts.  These  additions  were  made  in  an 
effort  to  increase  the  fluidity  of  the  pitch  somewhat  without  reducing 
•its  "  substantiality  "  and  to  avoid  the  necessity  of  heating  it  on 
the  work  during  application.  These  additions  had  the  desirable 
effect  of  lowering  the  melting-point  of  the  pitch  about  10  deg.  Fahr. 
(5.5  deg.  Cent.)  without  increasing  its  hardness. 

Four  pitches  were  tested  having  the  following  melting-points: 
75,  85,  95  and  105  deg.  Fahr.  (24,  29.5,  35  and  40.5  deg.  Cent,  respec- 
tively). (Cube-in-water  Method.) 

The  three  asphalts  used  to  make  the  5  per  cent  additions  had  the 
following  melting-points:  107,  154  and  182  deg.  Fahr.  (42,  68  and 
83  deg.  Cent.).  (Cube-in-water  Method.) 

The  oil  used  was  a  good  quality  raw  linseed  oil. 

Sixteen  samples  of  pitch  were  weighed  out  in  pint  cans  and 
each  set  of  four  of  equal  melting-point  received  an  addition  of  5  per 
cent  by  weight  of  one  of  the  three  different  asphalts  or  the  oil.  These 
were  then  heated,'  thoroughly  stirred,  and  allowed  to  cool  to  about 
75  deg.  Fahr.  (24  deg.  Cent.)  which  was  approximately  the  tem- 
perature of  the  compressed  air  chamber  under  about  21  pounds 
pressure.  On  reaching  this  temperature  each  sample  was  troweled 
onto  the  surface  of  pieces  of  treated  fabric  until  a  3-ply  membrane 
was  built  up  on  planed  boards  as  a  ground  work.  None  of  the 
pitches  was  fluid  enough  to  be  mopped  on,  hence  the  troweling. 
The  boards  were  then  inclined  at  an  angle  of  45  degrees  for  seventy- 
two  hours  to  compare  the  relative  amount  of  sliding  of  each  mem- 
brane. Table  XIV  shows  the  results  obtained  from  the  various  mixes. 

Specimens  Nos.  2  and  5  appear  to  be  best  suited  for  the  purpose, 
because  at  the  temperature  under  which  they  will  be  used,  they  are 
both  more  substantial  and  v/orkable  than  the  others.  Finally, 
since  the  admixture  of  linseed  oil  greatly  increases  the  cost  of  the 
product,  the  one  (No.  5)  with  an  admixture  of  asphalt  is  to  be  pre- 
ferred. 

Effect  of  Asbestos  Filler  on  the  Physical  Properties  of  Bitumen.* 
The  purpose  of  this  test  was  to  determine  whether  any  real  benefit 

*  Test  made  in  Chemical  Laboratory  of  the  Public  Service  Commission  for  the 
First  District,  State  of  New  York,  R.  LT  Oberholser,  Chief  Chemist. 


TECHNICAL  AND  PRACTICAL  TESTS  ON   WATERPROOFING    239 


§6 
22 


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240 


WATERPROOFING  ENGINEERING 


accrues  to  waterproofing  asphalt  by  the  incorporation  of  asbestos 
of  the  shredded  or  fibrous  variety,  as  was  the  practice  on  some  of 
the  subway  work  in  New  York  City. 

In  preparing  the  specimens  the  bitumen  was  heated  until  liquefied 
and  the  various  amounts  of  asbestos  added  and  stirred  until  the 
mixture  was  a  homogeneous  mass.  Table  XV  shows  the  results 
of  the  test. 


TABLE   XV.— EFFECT   OF   INCORPORATING   ASBESTOS   FIBER   IN 

BITUMEN 


Specimen 
Number. 

CONTENTS,  PER  CENT. 

Ductility 
at  32 
Degrees 
Fahren- 
heit. 

Ductility 
at  62 
Degrees 
Fahren- 
heit. 

Ductility 
at  77 
Degrees 
Fahren- 
heit. 

Melting- 
point 
Kraemer 
and  Sarnow 
Method, 
Degrees 
Fahrenheit. 

Pitch. 

Asphalt. 

Asbestos. 

1  
2  
3  

100 

99£ 
99 
98£ 
98 
97 

0 

i 

i 

H 

2 
3 
0 
i 
1 

H 

2 
3 

U 
l 
3 
H 
2 

3 
4 
1 
2 
2 

13 
11 
10 

8 
8 

7 
7 
8 
8 
9 

35 
17 
16 
7 
13 
7 
20 
10 
11 
13 
11 
10 

100 
110 
113 
119 
140 
119 
126 
130 
128 
165 
154 
143 



4  
5 

6 

7  
8  
9 

100 
99£ 
99 

98£ 
98 
97 

10 

11  
12  

The  most  evident  conclusions  from  this  test  are,  that  due  to  the 
presence  of  the  asbestos  the  ductility  of  the  bitumen  is  considerably 
decreased  and  the  melting-point  is  increased.  The  former  fact 
indicates  that  the  mixed  bitumen  would  not  hold  together  in  the  form 
of  a  thin  coating  as  well  as  the  pure  bitumen,  while  the  latter  indicates 
that  the  mixed  bitumen  would  flow  with  greater  diffculty  than  the 
pure  bitumen  at  the  same  temperature. 

Ductility  of  Asphalt  Containing  Coal-tar  Pitch.  The  purpose  of 
this  test  is  to  determine  the  effect  on  the  ductility  of  asphalt  of  the 
addition  of  coal-tar  pitch  in  various  percentages.  Both  the  asphalt 
and  the  pitch  were  of  the  grade  regularly  used  in  waterproofing  the 
dual  subways  in  New  York. 

The  melting-point  of  the  pitch  was  about  116  deg.  Fahr.  (47  deg. 
Cent.)  by  the  cube-in-water  method,  and  the  asphalt  about  120 
deg.  Fahr.  (49  deg.  Cent.)  by  the  Kraemer  and  Sarnow  method. 


TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING    241 

Starting  with  the  pure  asphalt  in  a  molten  condition  the  mix- 
tures were  made  by  adding  the  pitch  in  increments  of  5  per  cent  by 
weight.  The  specimens  were  then  tested  and  gave  the  following 
results:  The  melting-points  of  the  mixtures  showed  a  decided  but 
not  constant  increase  with  increase  of  pitch.  The  penetration  of 
the  mixtures  showed  an  almost  constant  decrease  and  at  propor- 
tions between  25  and  40  per  cent  of  asphalt  the  penetration 
approached  zero.  The  addition  of  30  to  40  per  cent  of  pitch  to  the 
asphalt  reduced  the  ductility  of  the  mixture  to  zero,  while  even  as 
little  as  5  per  cent  reduced  the  asphalt's  ductility  from  more  than 
100  to  30  or  40  cm.  It  seems,  therefore,  inadvisable  to  mix  coal- 
tar  pitch  and  asphalt  when  this  is  intended  for  waterproofing  by  the 
membrane  system.  It  may,  though,  be  good  as  a  waterproof  or 
dampproof  surface  coating  on  masonry  suited  for  its  application, 
or  as  a  roof  flashing  compound.  A  waterproofing  membrane  must 
be  elastic  and  ductile  to  a  reasonable  degree  to  avoid  cracking  in 
conjunction  with  the  structure  it  surrounds.  Mixing  these  two 
materials  tends  to  vitiate  this  by  giving  the  product  the  property  of 
"  shortness,"  or  lack  of  ductility. 

It  should  be  remembered,  however,  that  inferior  grades  of 
pitch  might  even  have  a  deleterious  effect  on  the  asphalt  or 
vice  versa. 

Effect  of  Temperature  on  Penetration  and  Ductility  of  Asphalt 
and  Coal-tar  Pitch.  The  penetration  and  ductilities  noted  in  these 
tests  were  made  with  the  Dow  penetrometer  and  tensometer,  both 
standard  testing  machines  used  in  asphalt  laboratories. 

Fig.  108,  which  is  quite  self-explanatory,  shows  that  according 
to  penetration  the  coal-tar  pitch,  though  of  lower  melting-point, 
and  tested  in  both  pure  and  mastic  forms,  is  harder  at  low  tem- 
peratures and  softer  at  high  temperatures  than  the  asphalt;  also 
that  the  asphalt  has  a  wider  temperature  range,  that  is,  the  asphalt 
is  less  affected  for  a  given  temperature  change  and  softens  more 
slowly  than  coal-tar  pitch. 

The  curves  in  Figs.  109  and  110  show  the  relative  penetration 
and  ductility  of  asphalt  and  coal-tar  pitch  whose  melting-points 
are  practically  equal,  as  determined  by  the  Kraemer  and  Sarnow 
method. 

From  a  study  of  the  penetration  curves  the  following  facts  may 
be  noted: 

(1)  The  asphalt  and  its  mastics  are  softer  than  coal-tar  pitch 
between  the  approximate  limits  of  40  and  90  deg.  Fahr.  (4.5  and 
32  deg.  Cent.). 


242 


WATERPROOFING  ENGINEERING 


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TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING    243 


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244 


WATERPROOFING  ENGINEERING 


(2)  The  coal-tar  pitch  curves  show  that  the  pitch  is  more  affected 
by  change  of  temperature  than  the  asphalt.     This  is  not  quite 
obvious,  however,  unless  we  assume  a  common  point  for  both  curves, 
which  would  very  likely  be  near  the  melting-point  of  both  materials. 
Then,  if  measured  from  this  point,  the  above  fact  is  readily  proved. 

(3)  Of  both  pitch  and  asphalt  mastics  the  pitch  mastic  of  pro- 
portions 2  :  2  :  1  is  more  affected  by  temperature  changes. 

(4)  Of  the  asphalt  mastics,  the  one  of  proportions  1:1:1  is 
least  affected  by  temperature  changes. 


Melting  Points  (K.&  S.Method) 
Asphalt  126°  F. 

Coal-tar  Pitch    103°  F. 


30 


110 


60  70 

Temperature,  Deg.  Fahr. 

FIG.  108. — Relation  of  Penetration  to  Temperature  of  Asphalt  and  Coal-tar 
Pitch;  also  Asphalt  and  Coal-tar  Pitch  Mastic,  Mixed  in  the  Proportions 
of  1  Part  Bitumen,  1  Part  Sand,  and  1  Part  Limestone  Dust.  (Points  of 
Curves  are  the  Means  of  three  Sets  of  Readings  on  Penetration  Machine 
Using  a  No.  2  Cambric  Needle,  Weighted  to  100  Grams  and  Acting  for 
Five  Seconds.) 

The  following  conclusions  are  noted  from  a  study  of  the  ductility 
curves : 

(a)  Asphalt  and  its  mastics  are  more  ductile  than  coal-tar  pitch 
(both  of  the  same  melting-point),  but  its  rate  of  change  of  ductility 
is  less,  hence  it  is  less  affected  by  temperature  changes. 

(6)  For  work  exposed  to  great  temperature  changes  the  asphalt 
is  to  be  preferred  to  coal-tar  pitch.  For  work  not  exposed  to  great 
temperature  changes  coal-tar  pitch  is  to  be  preferred  on  account  of 
its  greater  chemical  stability. 


TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING    245 


246 


WATERPROOFING  ENGINEERING 


TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING    247 

Comparative  Tests  on  Coal-tar  and  Asphalt  Mastics.*  Here- 
tofore asphalt  alone  Has  been  used  for  making  mastic  for  brick-in- 
mastic  usually  used  for  waterproofing  underground  structures.  The 
purpose  of  these  tests  was  to  ascertain  the  adaptability  of  straight- 
run  coal-tar  pitch  for  making  mastic  for  the  same  purpose. 

The  tests  were  made  to  cover  the  requisite  properties  of  a  mastic 
for  waterproofing  by  this  method,  these  properties  being  as  follows: 

(1)  The  mastic  must  have  a  small  and  limited  compressibility 
at  a  temperature  between  32  deg.  Fahr.  (0  deg.  Cent.)  and  77  deg. 
Fahr.  (25  deg.  Cent.) 

(2)  It  must  be  flexible  or  pliable,  that  is,  it  must  be  able  to  bend 
on  itself  without  fracture  at  40  deg.  Fahr.  (4.5  deg.  Cent.)  or  less. 

(3)  It  must  be  adhesive  and  cohesive  enough  to  heal  at  40  deg. 
Fahr.  or  less. 

(4)  It  must  be  tough  enough  at  32  deg.  Fahr.  to  resist  cracking 
due  to  impact  and  vibration  caused  by  moving  loads. 

(5)  It  must  be  reasonably  ductile  at  temperatures  between  32 
deg.  Fahr.  and  77  deg.  Fahr. 

(6)  It  must  be  of  uniform  consistency  however  proportioned. 

(7)  The  extracted  bitumen  must  have  very  little  (not  more  than 
3  per  cent)  volatile  oil. 

(8)  The  mineral  aggregate  must  pass  100  per  cent  through  a 
10-mesh  sieve. 

Two  kinds  of  coal-tar  pitch  and  one  of  asphalt  were  used  in 
making  the  test  specimens.  One  pitch  was  a  straight-run  product 
meeting  the  specifications  given  on  page  281;  the  other  was  also  a 
straight-run  product  brought  down  to  the  same  penetration  as  the 
asphalt  under  test.  The  asphalt  was  a  refined  Mexican  oil  made 
to  meet  the  specifications  given  on  page  282. 

Two  sets  of  tests  were  made.  In  one,  the  ingredients  were  pro- 
portioned by  weight — one  sand,  one  limestone  dust  or  cement, 
four  bitumen.  In  the  other,  the  ingredients  were  proportioned 
by  volume — one  sand,  one  limestone  dust  or  cement,  two  bitumen. 

The  reason  for  making  two  sets  of  tests,  one  with  about  twice  as 
much  bitumen  as  the  other,  was  to  ascertain  the  relative  effect  on 
the  properties  of  the  mastic  by  the  presence  of  more  or  less 
bitumen. 

Since  in  the  past  asphalt  mastic  has  been  used  exclusively  in  the 
brick-in-mastic  system  of  waterproofing,  and  since  there  is  no 
reported  failure  of  this  method  or  material,  it  was  accepted  as  the 

Test  made  under  supervision  of  author  in  the  Research  Laboratory  of  the 
Barrett  Company,  in  1915. 


248  WATERPROOFING  ENGINEERING 

standard,  i.e.,  all  results  were  compared  to  the  results  obtained  on 
the  asphalt  mastic.  These  values,  given  in  Table  XVI,  were  averaged 
and  the  following  conclusions  are  drawn  from  a  study  of  this 
table: 

(1)  A  limited  amount  of  compressibility  being  both  useful  and 
necessary  in  a  bituminous  mastic,  this  property  shows  up  generally 
in  favor  of  the  hard-pitch  mastic. 

(2)  Penetration — a    measure    of   the    hardness    of    the    mastic, 
but  not  a  very  reliable  test,  owing  to  the  presence  of  sand  particles — 
is  generally  in  favor  of  the  hard-pitch  mastic. 

(3)  The  bending  test,  showing  the  temperature  at  which  fracture 
will  occur,  shows  in  favor  of  the  soft-pitch  mastic ;  this  may  be  bent 
at  about  140  deg.  Fahr.  (60  deg.  Cent.)  lower  than  the  hard-pitch 
mastic. 

(4)  The  healing  test,  probably  the  most  important,  indicating 
the  inherent  capacity  of  the  mastic  to  restore  itself  after  cracking, 
shows  in  favor  of  both  pitch  mastics. 

(5)  The  impact  test,  indicating  the  resiliency  of  the  mastics, 
a  property  important  for  the  conditions  under  which  the  material 
is  usually  used,  shows  in  favor  of  the  soft-pitch  mastic. 

(6)  The  ductility  test,  indicating  the  tenacity  of  the  material, 
shows  in  favor  of  the  soft-pitch  mastic. 

(7)  The  gas-drip  test,  indicating  the  capacity  of  the  material  to 
resist  the  deteriorating  effect  of  gas-polluted  earth,  shows  in  favor 
of  both  the  pitch  mastics.     This  resistance  is  mainly  due  to  the 
presence  of  the  free  carbon  in  the  pitches,  but  is  obviously  not  a 
governing  property. 

From  the  foregoing  it  is  evident  that  both  pitches  are  better 
in  some  of  the  desirable  properties  than  the  asphalt,  but  neither 
excels  in  all  the  requisite  properties.  But  by  interpolating  the  results 
given  in  the  table,  a  grade  of  coal-tar  pitch  was  evolved,  meeting 
the  specifications  for  brick-in-mastic  waterproofing  given  in  Chapter 
VIII,  and  this  may  be  used  under  the  same  conditions  where  the 
asphalt  mastic  is  used. 

Volume  Reduction  of  Asphalt  Mastics.  In  the  mastic  and  water- 
proofing industries  it  is  a  matter  of  common  knowledge  that  the 
volume  of  the  finished  mastic  is  not  equal  to  the  total  volume  of  its 
ingredients,  just  as  in  the  case  of  concrete.  The  loss  in  volume  was 
assumed  to  be  anywhere  between  5  and  20  per  cent.  The  follow- 
ing test  was  therefore  made  to  determine  this  value  with  closer 
approximation : 

Equal  volumes  of  asphalt,  sand  and  cement  were  mixed  in  a 


TECHNICAL  AND   PRACTICAL  TESTS  ON  WATERPROOFING    249 

fire-heated  kettle  until  a  satisfactory  mastic  was  formed.  The  volume 
was  then  measured  and  found  to  be  approximately  30  per  cent  less 
than  the  total  volume  of  ingredients. 

Another  mastic  was  then  made  with  equal  volumes  of  asphalt 
and  mineral  aggregate;  the  latter  composed  of  one  part  cement  and 
three  parts  sand.  This  mixture  showed  about  20  per  cent  loss  in 
volume.  Other  mixtures  were  made  and  showed  losses  between  these 
limits  depending  on  the  proportions  of  sand  and  cement  in  the  mineral 
aggregate,  and  the  length  of  time  the  mastic  was  stirred.  This 
established  the  fact  that  20  per  cent  and  not  5  per  cent  is  the  mini- 
mum, and  about  30  per  cent  the  maximum  reduction  of  volume  for 
mastic  used  with  bricks  to  form  what  is  known  as  the  brick-in- 
mastic  waterproofing  envelope.  But  even  these  figures  are  materi- 
ally affected  by  the  duration  of  the  mixing  process,  the  volume 
further  decreasing  with  prolonged  stirring. 

Mastic  Bond  Affected  by  Surface  Condition  of  Bricks.  In  an 
effort  to  determine  the  relative  bonding  power  of  waterproofing 
mastic  on  bricks  in  various  conditions,  the  following  test  was  made: 

Five  bricks  were  embedded  in  a  50  per  cent  asphalt  mastic,  that 
is,  a  mastic  composed  of  fifty  parts  asphalt  and  fifty  parts  mineral 
matter.  The  first  brick  embedded  was  dry  and  clean;  this  was 
followed  by  a  moist  brick,  then  by  a  wet  brick,  then  by  two  bricks 
somewhat  blackened  with  soot,  as  would  be  the  case  if  the  bricks 
were  dry  heated  over  an  open  wood  fire,  as  is  often  done.  When  the 
mastic  cooled  and  hardened  the  bricks  were  pulled  up  and  showed 
the  following: 

(1)  The  dry  and  clean  brick  could  not  be  extracted  from  the 
mastic  intact. 

(2)  The  moist  brick  showed  but  little  bond  and  was  easily 
extracted. 

(3)  The  wet  brick  showed  no  bond  at  all. 

(4)  The  soot-blackened  bricks  showed  fairly  good  bond,  enough 
to  demonstrate  that  a  thin  coat  of  soot  is  not  objectionable  in  brick- 
and-mastic  work. 

Relative  Compression  of  Plain  Brick,  Brick  and  Mortar  and  Brick- 
in-mastic.  The  brick-in-mastic  specimens  were  made  in  accord- 
ance with  prevailing  practice,  that  is,  two  bricks  were  laid  in  mastic, 
side  by  side,  on  their  largest  bed,  as  stretchers.  But  for  testing,  the 
specimens  were  not  incased  in  concrete,  as  is  usually  done  in  prac- 
tice. The  specimens  were  four  bricks  high,  with  a  minimum  of 
|-inch  joints  and  each  completely  covered  with  asphalt  mastic.  The 
proportions  of  the  mastic  ingredients  were  about  40  per  cent  asphalt, 


250 


WATERPROOFING  ENGINEERING 


30  per  cent  sand  and  30  per  cent  cement,  by  weight.  The  bricks 
were  the  ordinary  building  variety,  2J  by  3f  by  8  inches. 

The  joints  of  the  wooden  form  used  for  making  the  specimens 
were  purposely  made  not  absolutely  tight,  as  this  is  a  condition  which 
occasionally  occurs  in  practice.  As  a  result,  some  of  the  hot  mastic 
leaked  out,  leaving  a  considerable  void  between  two  bricks  above 
the  level  of  the  leak. 

One  of  the  forms  was  also  made  somewhat  narrow,  that  is,  its 
width  did  not  permit  more  than  about  a  -j^-inch  joint.  The  result 
was  that  on  inserting  the  brick  the  mastic  was  squeezed  out  between 
the  form-side  and  brick.  The  latter  was  in  consequence  only  partly 
covered  with  mastic. 

These  conditions  illustrate  the  necessity  of  making  tight-joint 
forms  and  also  wide  enough  to  allow  sufficient  mastic  between  all 
brick  faces. 

Three  specimens  were  made  as  above  noted  (in  good  forms)  and 
when  tested  for  compression  at  about  70  deg.  Fahr.  (21  deg.  Cent.), 
gave  the  results  noted  in  Table  XVII,  to  which,  also,  are  added  for 
comparison,  the  ultimate  compressive  strength  of  plain  brick  and 
brick  and  mortar. 


TABLE   XVII.— ULTIMATE   COMPRESSIVE   STRENGTH    OF    BRICK 
AND   MASTIC,    BRICK   AND    MORTAR   AND   PLAIN   BRICK 

ULTIMATE  COMPRESIVE  STRENGTH 
(Lb.  per  Square  Inch) 


Brick  and  Mastic. 

Brick  and  Mortar.* 

Plain  Bricks.f 

360 

2520(a) 

5120 

281 

2440  (a) 

5060 

421 

3776(6) 

4880 

*Compression  on  column./S  X8  inch  base,  1  foot  4  inches  high,  of  common  brick  and  mortar, 
(a)   Lime  mortar,  1  :  3  proportion;  (6)   Portland  cement  mortar,  1  :  2  proportion, 
t  Compression  on  largest  bed  of  single  bricks. 

On  all  three  tests  of  the  brick-in-mastic,  the  bricks  failed  first. 
The  reason  for  this  is  that  the  mastic,  when  compressed,  tends  to 
spread  and  actually  does  so,  and  however  slight  this  may  be,  it 
places  the  brick  under  a  transverse  tension,  consequently  reducing 
its  compressive  strength,  as  indicated  in  the  table  above.  However, 
it  should  be  borne  in  mind  that  the  compressive  strength  of  brick- 
in-mastic  would  be  increased  considerably,  perhaps  quadrupled, 
by  being  encased  in  concrete,  as  it  actually  is  in  practice.  The 
temperature  of  the  brick-in-mastic  will  also  have  a  marked  effect 


TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING    251 

upon  its  strength.  A  continued,  comparatively  low  temperature, 
however,  will  not  prevent  the  ultimate  destruction  of  the  bricks  by 
transverse  tension,  but  only  retard  it,  unless,  of  course,  the  brick- 
in-mastic  is  well  encased  in  masonry  to  prevent  it. 

Effect  of  Temperature  of  Saturants  on  Waterproofing  Fabrics. 
The  purpose  of  this  test  was  to  determine  (1)  the  effect  of  high  tem- 
peratures on  waterproofing  felt  and  fabrics  while  in  course  of  treat- 
ment; (2)  the  charring  temperature  of  these  materials;  (3)  the 
result  of  treating  fabrics  without  the  use  of  the  usual  compression 
rollers. 

Specimens  of  cotton  drill  and  open-mesh  jute  burlap  were  cut 
into  workable  pieces  and  treated  as  follows:  Eighteen  pieces  were 
saturated  with  asphalt  at  different  temperatures  ranging  from  180 
deg.  Fahr.  (82  deg.  Cent.)  to  500  deg.  Fahr.  (260  deg.  Cent.),  raised 
by  increments  of  30  deg.  Fahr. ;  fourteen  pieces  were  saturated  with 
coal-tar  pitch  at  different  temperatures  ranging  from  180  deg.  Fahr. 
to  420  deg.  Fahr.  (215.5  deg.  Cent.)  raised  by  increments  of  25  deg. 
Fahr. ;  ten  pieces  were  saturated  with  a  mixture  of  asphalt  and  coal- 
tar  pitch  in  equal  proportions;  the  temperatures  of  the  mixture 
ranged  from  300  deg.  Fahr.  (149  deg.  Cent.)  to  520  deg.  Fahr.  (271 
deg.  Cent.),  raised  by  increments  of  50  deg.  Fahr. 

The  melting  point  of  the  pitch  used  was  about  120  deg.  Fahr. 
(49  deg.  Cent.)  and  that  of  the  asphalt  about  160  deg,  Fahr.  (71  deg. 
Cent.),  both  determined  by  the  cube-in-water  method. 

The  method  of  saturating  the  forty -two  specimens  was  as  follows: 
Each  piece  was  drawn  slowly,  as  in  practice,  through  its  saturant, 
completely  immersed,  and,  when  withdrawn,  was  hung  up  imme- 
diately to  dry  in  the  air.  Of  course,  this  is  not  the  method  used  by 
manufacturers  of  waterproofing  products  for  treating  fabrics.  At 
the  factory  the  felts  and  fabrics  are  drawn  through  steam-heated 
compression  rollers  immediately  after  they  leave  t:^e  saturating  tank, 
which  operation  forces  the  compound  into  the  fibers  and  removes 
the  excess  saturating  material.  (See  Fig.  60.) 

It  was  interesting  and  instructive  to  know  though  what  the  re- 
sulting condition  of  the  product  is  when  treated  as  above.  All  were 
well  saturated  but  excessively  coated  with  bitumen.  The  burlap 
specimens  showed  very  few  or  no  open  meshes  remaining.  Both  the 
asphalt-  and  pitch-saturated  specimens,  when  weighed,  showed  a 
gradual  decrease  in  the  amount  of  saturant  with  the  increase  of  tem- 
perature, but  the  "  A.-P."  (asphalt-pitch)  mixture  saturated 
specimens  showed  almost  constant  weight  of  saturant  notwithstand- 
ing increase  of  temperature;  in  other  words,  the  "  A.-P."  mixture 


252  WATERPROOFING  ENGINEERING 

remained  at  practically  the  same  consistency  while  the  others  became 
more  fluid.  The  pitch-saturated  fabrics  lost  their  tackiness  first,  then 
the  "A.-P."  saturated  fabrics  and  lastly  the  asphalt-saturated  fabrics. 
The  "  A.-P/'  mixture  saturated  specimens  were  devoid  of  ductility, 
cracked  easily  on  being  bent  around  the  finger  at  normal  tempera- 
ture and  showed  a  dull-black,  rough  and  pitted  surface.  The 
asphalt-saturated  and  pitch-saturated  samples  showed  a  smooth 
and  lustrous  surface. 

Several  specimens  of  untreated  felt,  raw  burlap  and  cotton  drill 
were  then  put  into  a  sand  bath  and  heated  gradually;  at  about 
400  deg.  Fahr.  (204.4  deg.  Cent.)  the  felt  charred;  at  425  deg.  Fahr. 
(218.3  deg.  Cent.)  the  burlap  charred  and  at  about  450  deg.  Fahr. 
(232.1  deg.  Cent.)  the  cotton  drill  began  to  char.  The  charring 
temperatures  thus  obtained  verified  previous  values  obtained  dur- 
ing the  saturation  process. 

Manifestly  the  fabrics  must  be  drawn  through  compression  rollers 
to  obtain  not  only  good  saturation  but  also  the  proper  amount  of 
coating  and,  in  the  case  of  burlap,  sufficient  open  mesh  in  the  finished 
product.  The  temperature  of  the  saturant  has  much  to  do  with 
the  degree  of  saturation  and  is,  in  fact,  almost  proportional  to  it. 
The  possibility  of  charring  the  felts  and  fabrics  during  treatment  is 
remote  because  such  temperatures  never  exceed  350  deg.  Fahr.  in 
practice  and  besides,  the  bitumen,  especially  the  pitch,  would  be 
injured  first  by  over-heating,  and  detected  by  the  excessive  fumes 
it  gives  off  at  the  higher  (charring)  temperatures.  The  saturant 
composed  of  equal  parts  of  asphalt  and  coal-tar  pitch  is  obviously 
not  as  good  as  either  of  the  other  two  when  used  as  a  saturant  for 
fabrics. 

RELATIVE  AMOUNT  OF  SATURANT  AND  COATING  MATERIAL  ON 
TREATED  WATERPROOFING  FELTS  AND  FABRICS 

It  has  often  been  stated  that  jute  fabric  cannot  be  saturated  as 
well  as  felt.  The  results  noted  in  Table  XVIII  indicate  that  this 
is  true  for  asphalt-treated  fabric  but  quite  the  reverse  for  pitch- 
treated  fabric.  It  must,  however,  be  borne  in  mind  that  the  satura- 
tion of  the  jute  fabric,  even  with  asphalt,  is  only  a  preliminary  step 
to  its  final  treatment,  while  with  the  saturation  of  the  felt  its  treat- 
ment is  completed.  This  is  true  of  most  asphalt-  and  all  pitch- 
treated  felts.  On  the  other  hand,  saturated  cotton  fabric  (satura- 
tion being  its  only  treatment)  has  25  per  cent  more  saturant  than 
the  felt. 


TECHNICAL  AND   PRACTICAL  TESTS  ON   WATERPROOFING    253 


TABLE  XVIII.— RELATIVE  AMOUNT  OF  SATURANT  AND  COATING 
ON  TREATED  WATERPROOFING  FELTS  AND  FABRICS 


No. 

Material. 

WEIGHT  IN  GRAMS  PER  SQUARE  FOOT. 

TREATED    MATERIAL 
(BASED  ON  RAW  MATE- 
RIALS). 

Un- 
treated. 

ASPHALT- 
TREATED. 

PITCH- 
TREATED. 

Satu- 
rated. 

Satu- 
rated 
and 
Coated. 

Satu- 
rated 

Satu- 
rated 
and 
Coated. 

Per 
Cent 
of 
Satu- 
rant. 

Per 

Cent 
of 
Coating 

Per 

Cent 
of 
Total 
Bitu- 
men. 

1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 

12 
13 
14 
15 
16 
17 
18 
19 

20 
21 
22 
23 
24 
25 

26 
27 
28 
29 
30 

31 
32 
33 
34 

35 
36 

37 
38 

Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Averages  .... 

21.70 
25.56 
20  30 
22.59 
21.60 
24.55 
21.60 
21.20 
19.95 
21.15 
22.00 
20.18 

21.70 
19.10 
20.35 
19.55 
18.45 
21.05 
22.50 
20.30 
20.30 

28.75 
25.25 
22.25 
28.89 
27.40 
20.55 
25.50 

29.90 
17.30 
26.20 
25.60 
21.60 
24.10 

59.35 
58.51 
50.60 
64.20 
73.80 
91.70 
66  .  40 

17.05 
19.30 
18.20 

29.80 
59.80 
35.82 
45.80 

71.30 
80.11 
61.82 
68.00 
50  35 

37.1 
133.0 
76.4 
102.0 

190.0 
79.4 
128.0 
98.0 

227 
213 
204 
202 
133 
150 
177 
124 
251 
256 
306 
203.9 

157 
295 
328 
251 
287 
286 
266 
286 
269.5 



33.65 

37.60 
36.55 

39.70 

61  .  45 
59.95 
47.50 
70.05 
75.35 
89.40 
61.20 

...".. 

37.0 

113.0 

88.0 
72.7 

162.0 
183.0 



47.05 
59.90 
52.10 
51.90 
62.30 
58.90 
64.20 
49.65 
55.70 

62.85 
65.00 
47.50 
66.17 
52.90 
35.62 
55.30 

56.00 
75.75 
87.25 
68.75 
71.60 
81.45 
82.70 
78.70 
75.30 

78.0 

116.0 
214.0 
155.0 
165.0 
237.0 
179.0 
185.0 
143.0 
174.0 

118.0 
156.0 
113.0 
135.0 
03.0 
73.2 
114.7 

165.0 
101.0 
116.0 
107.0 
106.0 
119.0 

104  0 

136.2 

41.2 
82.9 
172.0 
86.1 
50.2 
107.0 
81.8 
142.0 
95.4 

Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Open-mesh  jute  fabric 
Averages  

Felt  (light  grade)      .  . 
Felt  (light  grade)     .  . 
Felt  (light  grade)     .  . 
Felt  (light  grade)      .  . 
Felt  (light  grade)     .  . 
Felt  (light  grade)     .  . 
Averages 

79.25 
34.70 
56.80 
53.05 
44.70 
53.70 

121.20 
182.14 
125.50 
157.60 
161.90 
157.10 
150.90 



Felt  (light  grade)     .  . 
Felt  (light  grade)    .  . 
Felt  (light  grade)     .  . 
Felt  (light  grade)     .  . 
Felt  (light  grade)      .  . 
Averages  

Felt  (heavy  grade)..  . 
Felt  (heavy  grade)..  . 
Felt  (heavy  grade)..  . 
Felt  (heavy  grade)  .  .  . 
Felt  (heavy  grade)  .  .  . 
Felt  (heavy  grade)  .  .  . 
Averages  

Cotton  fabric  
Cotton  fabric  
Averages  



211  0 

146  0 

145  0 

119  0 

71  0 

132  7 

43.05 
45  52 





152.0 
135  0 





44.30 

143.5 



254  WATERPROOFING  ENGINEERING 

It  has  also  been  stated  that  an  asphaltic-treating  compound  for 
jute  fabric  intended  for  membrane  waterproofing  with  coal-tar 
pitch  as  a  binder  is  injurious  to  the  membrane  because  the  two 
materials  are  forced  to  mix  (on  account  of  the  binder  being  applied 
hot),  and  produce  thereby  an  inelastic  and  perhaps  deleterious 
compound.  Careful  investigation,  however,  seems  to  show  that 
the  amount  of  treating  compound  used  in  the  fabric  is  so  little  in 
comparison  with  the  amount  of  binder  used  in  the  membrane  that 
there  is  no  apparent  harm  in  using  asphalt-treated  fabric  with  coal- 
tar  pitch  binder.  The  results  of  weights  of  specimens  noted  in  Table 
XVIII  permit  the  determination  of  the  proportion  of  treating  com- 
pound to  binder  used  to  form,  say,  a  3-ply  or  a  6-ply  membrane; 
for  instance,  a  square  foot  of  a  3-ply  fabric  membrane,  approximately 
J-inch  thick,  weighs  2  pounds,  of  which  80  per  cent  is  pitch-binder 
and  15  per  cent  asphaltic-treating  compound.  Pitch  and  asphalt 
in  these  proportions,  were  they  actually  mixed,  would  not  produce 
a  very  bad  compound  to  be  used  as  a  binder.  In  the  field,  not  more 
than  the  coating  on  the  fabric  mixes  with  the  binder,  therefore 
the  percentage  of  treating  compound  that  mixes  with  the  binder 
is  still  less  than  that  given  here. 

Further  facts  disclosed  in  Table  XVIII  are  that  though  asphalt- 
treated  jute  fabric  has  only  about  75  per  cent  as  much  total  bitumen 
(that  is,  saturant  plus  coating  material)  as  the  pitch-treated  fabric, 
the  amount  of  coating  proper  on  the  asphalt-treated  fabric  is  45  per 
cent  greater  than  that  on  the  pitch-treated  fabric. 

Asphalt-treated  and  pitch-treated  felts  of  approximately  the  same 
weights  are  equally  well  saturated,  but  heavy  felts  contain  about 
10  per  cent  more  saturant  than  lighter  felts. 

Effect  of  Drinking  Water  on  Waterproofing  Fabrics.  The  pur- 
pose of  this  test  is  to  determine  the  effect  on  treated  and  untreated 
fabric  of  one-half  year's  immersion  in  water  and  one-half  year's 
gradual  drying. 

In  March,  1914,  nine  specimens  of  jute  fabric,  some  treated  with 
asphalt  and  some  with  coal-tar  pitch  and  one  untreated  specimen, 
were  immersed  in  plain  water,  contained  in  a  rectangular  tank 
1  by  1  by  3  feet.  The  specimens  were  suspended  from  strings 
stretched  across  the  tank  and  labeled  for  identification.  The 
water  was  constantly  replenished  for  six  months  after  which  it 
was  allowed  to  evaporate  completely,  which  also  took  about  six 
months. 

In  March,  1915,  the  specimens  were  carefully  examined,  and  the 
following  results  noted.  The  untreated  jute  burlap  though  thor- 


TECHNICAL  AND   PRACTICAL  TESTS  ON   WATERPROOFING    255 

oughly  wet  for  at  least  six  months,  had  retained  its  strength  com- 
pletely but  was  a  little  stiff  and  darker  in  color  than  originally. 
The  bituminous  treated  specimens  showed  hardly  any  loss  of  strength 
and  practically  no  deterioration.  Where  the  coating  on  the  fabric 
was  good  originally,  the  fabric  was  entirely  unaffected,  that  is,  no 
water  penetrated  the  fabric  fibers.  The  bitumen  retained  its 
elasticity  and  the  fine  sawdust,  which  is  sprinkled  on  the 
surface  of  the  fabric  to  prevent  self  adhesion  in  the  rolls 
during  shipment  and  storage,  remained  intact.  Where  the  fabric 
was  poorly  saturated,  a  slight  loss  of  tensile  strength  was  mani- 
fested. In  general,  however,  the  asphalt  treated  specimens  showed 
somewhat  less  resistance  than  the  specimens  of  fabric  treated  with 
coal-tar  pitch. 

The  test  proves  (1)  the  value  of  thoroughly  coating  and  saturating 
the  fabric,  because  thereby  it  is  prevented  from  absorbing  water, 
and  (2)  that  plain  water  is  not  particularly  injurious  to  bituminous 
treated  fabric. 

Effect  of  Ground  Water  on  Waterproofing  Fabrics.  To  deter- 
mine the  effect  on  fabrics  treated  with  asphalt  and  with  coal-tar 
pitch  by  the  action  of  ground  water  in  direct  contact  with  them, 
thirteen  specimens  of  treated  jute  fabric,  each  about  4  by  6  inches, 
were  buried  about  3  feet  in  the  ground  at  City  Hall  Park,  N.  Y., 
near  the  new  Broadway  Subway  location,  for  a  period  of  106  days 
(from  May  6th  to  August  22d,  1914).  Table  XIX  shows  the  char- 
acteristics of  the  interred  waterproofing  fabric. 

In  another  test  similar  to  the  above,  various  grades  of  cotton 
fabric,  paper  fabric  and  felt  were  buried  in  the  ground  at  Battery 
Park,  N.  Y.,  at  a  depth  of  4  feet.  In  less  than  three  months,  when 
the  specimens  were  examined,  it  was  found  that  the  cotton  and 
paper  fabrics  had  almost  completely  decayed  and  the  felt  had  become 
so  brittle  that  it  broke  in  handling. 

Another  test  of  a  similar  nature  with  various  cotton,  jute  and  felt 
specimens,  but  this  time  each  heavily  coated  with  pitch  or  asphalt, 
showed  on  examination,  after  2£  months'  burial,  that  both  the  fabric 
and  felt  were  well  preserved  though  the  coatings  were  considerably 
pitted. 

In  each  of  the  above  tests  the  specimens  were  obtained  from 
various  manufacturers. 

These  tests  conclusively  prove  the  necessity  of  thoroughly  coat- 
ing any  felt  or  fabric  used  as  reinforcement  in  a  bituminous  water- 
proofing membrane.  Also  that  the  binder  and  not  the  felt  or 
fabric  is  the  waterproofing  material  in  such  a  membrane- 


256 


WATERPROOFING  ENGINEERING 


TABLE  XIX.— EFFECT  OF  GROUND  WATER  ON  WATERPROOFING 

FABRICS 


BEFORE  BURYING. 


(1).  7  oz.  open-mesh  asphalt- treated 
fabric;   well  saturated  and  coated. 


2.  7  oz.  open-mesh  asphalt- treated 
fabric;  well  saturated,  one  side  well 
coated,  other  side  poorly  coated. 

(3).  7  oz.  open-mesh  asphalt- treated 
fabric;  well  saturated  and  coated. 

(4).  7  oz.  open-mesh  asphalt-treated 
fabric;  poorly  coated;  not  saturated. 

(5)  8  oz.  open-mesh  oil-tar  pitch- 
treated  fabric;  poorly  saturated  but 
well  coated;  pliable. 

(6).  8  oz.  open-mesh  oil-tar  pitch- 
treated  fabric;  well  saturated  and 
coated;  somewhat  stiff  and  brittle 
coating. 

(70-  Seven  pieces  of  7  oz.  open -mesh 
asphalt-  and  pitch-treated  fabric,  more 
or  less  well  saturated  and  coated. 


AFTER  BURYING. 


Shows  almost  complete  decay.  Both 
asphalt  and  burlap  are  very  brittle. 
No  "  life  "  left. 

Shows  no  strength.  Asphalt  coating 
very  brittle.  Burlap  saturated  with 
water. 

Shows  brittleness  and  more  or  less 
decay.  Lacks  strength. 

Shows  almost  complete  decay.  Very 
brittle. 

Shows  almost  complete  decay.  Re- 
mainder is  pliable  but  weak. 


Is    brittle,    weak    and    decayed    in 
several  spots. 


Specimens  so  badly  deteriorated  that 
identification  is  impossible. 


Relative  Absorption  and  Strength  of  Raw  and  Treated  Water- 
proofing Felts  and  Fabrics.  To  determine  the  relative  amount  of 
water  absorbed  by  various  waterproofing  felts  and  fabrics,  and 
also  their  relative  tensile  strength  and  stretch,  88  specimens,  of 
which  35  were  untreated,  and  the  remainder  treated  with  either 
asphalt  or  pitch,  were  partly  immersed  in  water  for  three  hours  and 
weighed  before  immersion  and  at  the  end  of  the  first  and  third  hours. 
Then  the  specimens  were  allowed  to  dry,  after  which  they  were 
cut  into  1-inch  strips  and  tested  for  strength  and  stretch  on  a 
stretching  machine.  A  review  of  Table  XX  reveals  the  following 
facts : 

1.  Untreated  jute  burlap  is  much  more  absorbent  than  paper 
fabric,  cotton  fabric,  felt,  building  paper,  and  ready-roofing,  all 
untreated, 


TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING    257 


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TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING    259 

2.  Saturated  (only)  jute  burlap  is  but  little  more  absorbent  than 
saturated  paper  fabric  and  felt,  but  much  less  absorbent  than  satu- 
rated cotton  fabric. 

3.  Untreated  jute  burlap  will  absorb  in  one  hour  about  70  per 
cent,  and  in  three  hours  about  80  per  cent  of  its  weight  of  water, 
while  the  same  burlap,  asphalt-saturated  and  coated,  will  absorb 
in  one  hour  only  about  2J  per  cent  and  in  three  hours  only  about  3J 
per  cent  of  its  weight  of  water;    while  the  oil-tar  saturated  and 
coated  burlap  will  absorb  in  one  hour  about  5  per  cent  and  in  three 
hours  about  6  per  cent  of  its  weight  of  water. 

4.  Untreated  paper  fabric  will  absorb  in  one  hour  about  20  per 
cent  and  in  three  hours  about  30  per  cent  of  its  weight  of  water, 
while  the  same  paper  fabric,  coated  either  with  asphalt  or  pitch, 
will  absorb  about  4  per  cent  of  its  weight  of  water  during  both 
periods. 

5.  Untreated  cotton  fabric  will  absorb  in  one  hour  about  24  per 
cent  and  in  three  hours  about  27  per  cent  of  its  weight  of  water, 
while  the  same  cotton  fabric,  treated,  will  absorb  in  one  hour  only 
14  per  cent  and  in  three  hours  only  15  per  cent  of  its  weight  of  water. 

6.  Untreated  felt  will  absorb  in  one  hour  about  55  per  cent  and 
in  three  hours  about  70  per  cent  of  its  weight  of  water,  while  the 
same  felt,  asphalt-treated,  will  absorb   about  2  per  cent  and  the 
tar-treated  felt  about  3|  per  cent  of  its  weight  of  water  during 
both  periods. 

7.  The  tensile   strength   (of   the  warp)   of  asphalt-treated  jute 
burlap  is  increased  about   100  per  cent    and  the  tar-treated  jute 
burlap  over  125  per  cent,  as  compared  to  the  untreated  burlap. 
The  percentage  of  stretch  is  diminished  by  treatment  and  is  less 
for  the  tar-treated  than  for  the  asphalt-treated  fabric. 

8.  The  tensile  strength  of  treated  paper  fabric  is  practically  the 
same  as  that  of  the  untreated,  but  the  stretch  is  only  about  50  per 
cent  as  great. 

9.  The  tensile  strength  of  treated  cotton  fabric  is  about  20  per 
cent  more  than  the  untreated,  but  the   stretch  is   about   200  per 
cent  greater. 

10.  The  tensile  strength  of  asphalt-treated  felt  is  increased  about 
300  per  cent,  and  the  tar-treated  felt  about  600  per  cent.     But  the 
stretch  is  the  same  for  both  treated  and  untreated,  this  being  an 
average  of  3  per  cent  in  a  2-inch  length. 

The  above  conclusions  are  based  on  consideration  only  of  the 
warp  of  the  fabrics. 

It  is  interesting  to  note  that  ordinary  blotting  paper  is  about  200 


260  WATERPROOFING  ENGINEERING 

per  cent  stronger  than  untreated  felt  of  the  same  weight,  but  is  about 
200  per  cent  more  absorbent,  though  their  unit  stretch  is  the  same. 

Immutability  Test  on  Various  Waterproofing  Felts  and  Fabrics. 
To  determine  the  effect  of  exposure  to  the  elements  for  a  period  of 
time,  thirty-four  specimens  of  waterproofing  felts  and  fabrics,  vari- 
ously treated,  were  left  in  the  open  air  completely  unprotected 
for  periods  ranging  from  five  to  ten  months.  During  the  time  of 
their  exposure  they  were  subjected  to  rain,  hail,  snow  and  sunshine. 
From  careful  examination  of  these  specimens,  the  following  facts 
are  made  evident  and  considered  as  warranting  attention:  (1)  The 
asphalt-treated  fabric  is  practically  unaffected  by  exposure.  (2) 
Oil-tar  pitch-treated  fabric  is  not  in  itself  affected,  but  tends  to 
become  stiff  from  the  evaporation  of  the  saturant  oils.  (3)  Raw 
and  pitch-treated  felts  are  practically  unaffected  except  for  the  latter, 
which  tend  to  harden  and  become  brittle,  due  to  the  evaporation  of 
the  saturant  oils. 

Hence  the  general  conclusion :  Pitch-treated  felts  or  fabrics  should 
not  be  stored  in  the  open  for  more  than  a  few  weeks  before  using,  and 
all  membrane  roofings  should  receive  a  top-coating  of  bitumen 
to  preserve  the  top  sheeting. 

Compressibility  of  Treated  Jute-fabric  Waterproofing  Mem- 
branes. The  purpose  of  this  test  was  to  ascertain  the  amount  of 
compression  that  a  waterproofing  membrane  can  withstand  without 
rupture. 

Six  membranes  were  tested,  two  composed  of  three  plies  each, 
placed  between  J-inch  mortar  discs;  two  composed  of  six  plies  each, 
also  placed  between  J-inch  mortar  discs,  and  one  composed  of  six 
plies  and  one  of  twelve  plies,  both  without  bituminous  binder  or 
mortar  protection  discs. 

The  asphalt  binder  used  in  making  half  the  specimens  had  a  melt- 
ing-point of  about  125  deg.  Fahr.  (52  deg.  Cent.)  by  the  K.  and  S. 
method,  and  the  pitch  binder  used  for  making  the  remaining  speci- 
mens had  a  melting-point  of  about  120  deg.  Fahr.  (49  deg.  Cent.) 
by  the  Cube-in- water  method.  The  temperature  of  the  specimens 
was  about  75  deg.  Fahr.  (25  deg.  Cent.)  when  tested. 

When  pressure  was  applied  to  each  of  the  first  four  membranes, 
the  mortar  discs  were  the  first  to  fail  at  about  1000  pounds  per  square 
inch,  the  membranes  remaining  uninjured.  At  about  2000  pounds 
per  square  inch  the  fabric  began  to  push  out  on  all  sides.  When 
pressure  was  released  and  the  membrane  examined  it  was  found  that 
when  the  membrane  began  to  push  out  radially  it  was  crushed  to 
destruction  at  the  center.  The  two  membranes  that  were  tested 


TECHNICAL  AND  PRACTICAL  TESTS  ON  WATERPROOFING     261 

without  the  binder  and  mortar  discs  were  not  affected  at  all  at  a 
pressure  of  about  3000  pounds  per  square  inch.  Both  these  mem- 
branes were  merely  compressed  and  became  as  hard  as  a  board. 
On  tearing  the  separate  plies  apart  each  of  them  was  found  to  be 
uninjured  except  for  the  bituminous  coating  with  which  the  fabric 
was  treated,  which  had  been  forced  into  the  open  mesh  of  the  fabric. 
This  test  demonstrates  that  a  built-up,  jute  fabric  membrane 
can  safely  withstand  a  direct  compression  of  1000  pounds  per  square 
inch;  that  both  pitch  and  asphalt  binder  of  the  melting-points  and 
at  the  temperature  indicated  above  behave  alike  for  membrane 
waterproofing  when  subjected  to  compression. 


CHAPTER  VIII 
WATERPROOFING   SPECIFICATIONS 

Specification  Requisites.  Many  architects  and  engineers  are 
not  sufficiently  familiar  with  waterproofing  engineering,  hence,  in 
writing  specifications,  abstractions  are  freely  made  from  one  speci- 
fication and  used  in  another.  Such  practice  is  inadvisable  and  should 
be  guarded  against.  In  writing  specifications  there  is  usually  re- 
quired some  of  the  lawyer's  skill  in  phraseology  and  the  experienced 
engineer's  knowledge.  For  those  not  so  fortunate  as  to  possess 
both  these  qualities,  a  few  remarks  on  the  writing  of  waterproofing 
specifications  will  not  be  amiss. 

The  specification  writer  should  avoid  being  general,  for,  to  be 
specific  is  the  first  requisite  of  good  specification  writing.  Water- 
proofing specifications,  as  indeed  all  specifications,  should  be  written 
open  enough  to  admit  of  fair  competition.  They  should  describe 
the  materials,  their  properties  and  application  well  enough  to  enable 
manufacturers  to  make  them,  contractors  to  apply  them,  and  engi- 
neers or  inspectors  to  approve  or  reject  the  materials  or  their  appli- 
cation, or  the  field  work  in  general,  on  the  strength  of  such  specifica- 
tions. They  should  be  suited  to  the  conditions  surrounding  the 
particular  work.  Sufficient  instructions  should  be  embodied  in  the 
specifications  to  enable  the  engineer  to  assure  himself  that  the  water- 
proofing work  can  be  properly  executed  under  them.  Equivocal 
or  incomplete  statements  should  be  avoided,  while  explanatory 
clauses  should  be  inserted  wherever  necessary.  The  application 
of  waterproofing  materials  is  more  difficult  and  important  than  their 
manufacture;  hence,  efficient  and  sufficient  supervision  should  be 
called  for.  Specific  laboratory  tests  should  also  be  called  for,  and 
these  should  be  basic,  not  supplemental  as  they  often  are  at  present. 
No  waterproofing  specifications  should  allow  a  variation  from  any 
numerical  requirement  for  strength  or  composition,  as  determined 
by  test,  of  anything  more  than  is  consistent  with  best  practice  for 
the  particular  property  under  consideration.  Such  values  are  given 
for  a  great  many  materials,  and  will  be  found  in  the  book  of  yearly 
proceedings  of  the  American  Society  for  Testing  Materials.  But 

262 


WATERPROOFING  SPECIFICATIONS  263 

while  the  results  of  some  acceptance  tests  may  vary  more  than  others 
the  governing  values  and  their  significance  should  be  well  understood 
before  rejecting  the  material  on  such  grounds.  Easy  identification 
and  proper  care  of  all  waterproofing  materials  in  the  field  should  be 
provided  for;  also,  access  to  the  manufactories  to  observe  the  mate- 
rials m  the  various  stages  of  their  manufacture.  The  intent  of  the 
specifications  should  be  carefully  set  forth;  the  price  agreed  upon — a 
lump  sum  or  per  unit  of  completed  work.  The  material  alternatives, 
the  guarantee  and  necessary  bonds  should  be  clearly  set  forth. 

These  few  suggestions  well  pondered,  and  a  careful  study  of  all 
the  conditions  under  which  the  work  of  waterproofing  is  to  proceed, 
coupled  with  a  knowledge  of  the  properties  of  waterproofing  mate- 
rials— all  in  the  hands  of  an  experienced  engineer  or  architect — would 
result  in  a  type  of  specification  under  which  litigation  would  be  almost 
impossible. 

The  specifications  considered  herein  are  fairly  representative 
of  the  advancement  that  the  art  of  waterproofing  has  made  and  which 
it  enjoys  to-day.  The  selection  is  varied  enough  to  be  of  assistance 
to  the  architect  or  engineer  in  drawing  up  waterproofing  specifica- 
tions for  many  kinds  of  structures.  The  specific  information  in 
each,  though  not  always  complete,  is  modern  and  in  accord  with 
present  practice.  Several  specifications  of  proprietary  waterproof- 
ing materials  are  included  for  their  suggestive  value.  The  same  is 
true  of  the  roofing  specifications.  Some  specifications  are  given  in 
full  while  only  abstracts  from  others  are  stated  to  avoid  cumbrance. 
A  few  original  specifications  and  several  specifications  of  the  more 
common  materials  used  in  waterproofing  engineering  are  included. 

By  a  careful  perusal  and  comparison  of  these  specifications,  it 
is  believed  the  architect  or  engineer  will  find  material  guidance  in 
drawing  up  explicit  and  practical  waterproofing  specifications. 

SPECIFICATIONS  FOR  WATERPROOFING  MATERIALS 

Treated  Woven  Cotton  Fabric  for  Membrane  Waterproofing. 

Woven  cotton  fabric  for  waterproofing  purposes  shall  be  made  of  a 
good  grade  of  cotton.  In  its  raw  or  untreated  state,  it  shall  contain 
no  oils  of  any  kind.  It  shall  weigh  not  less  than  5  ounces  to  the 
square  yard  and  its  thread  count  shall  not  be  less  than  50  by  60 
per  square  inch.  To  be  made  into  a  waterproofing  fabric,  it  shall  be 
thoroughly  saturated  with  either  asphalt  or  coal-tar  pitch  meeting 
the  requirements  hereinafter  specified.  No  oils  or  bitumen  solvents 
shall  be  used  to  liquefy  either  the  asphalt  or  pitch  in  order  to  produce 


264  WATERPROOFING  ENGINEERING 

a  thoroughly  saturated  fabric.  The  fabric  after  treatment  shall 
weigh  not  less  than  three  and  one-half  times  the  weight  of  the 
untreated  fabric.  During  treatment,  the  temperature  of  the  satu- 
rating material  shall  not  exceed  275  deg.  Fahr.  (135  deg.  Cent.). 
The  fabric  after  treatment  shall  be  elastic  and  have  a  stretch  in 
either  direction  of  at  least  five  (5)  per  cent  without  fracture.  A 
1-inch  strip,  cut  with  the  warp,  shall  sustain  a  weight  of  at  least  60 
pounds,  and  at  least  50  pounds  with  the  woof.  It  must  be  flexible  at 
all  temperatures  between  32  deg.  Fahr.  and  150  deg.  Fahr.  (0  to  66 
deg.  Cent.),  and  shall  not  flake  or  crack  when  folded  upon  itself. 
It  must  be  of  such  a  nature  as  to  readily  conform  to  any  unevenness 
of  the  surface  to  which  it  is  applied. 

The  asphalt  for  treating  the  woven  cotton  fabric  shall  be  a  refined 
product  meeting  the  following  requirements:  Its  melting-point 
by  the  Kraemer  and  Sarnow  method  shall  be  155  deg.  Fahr.  (68 
deg.  Cent.);  its  penetration  by  the  Dow  method  shall  be  .30  cm., 
and  its  ductility  not  less  than  10  cm.  nor  more  than  20  cm.  as  meas- 
ured on  a  Smith  ductility  machine. 

The  tar  pitch  for  treating  the  woven  cotton  fabric  shall  be  a 
straight-run,  coal-tar  pitch  meeting  the  following  requirements: 
Its  melting-point  by  the  cube-in-water  method,  shall  be  110  deg. 
Fahr.  (43  deg.  Cent.);  its  penetration  by  the  Dow  method,  shall 
be  1.5  cm.;  the  loss  on  heating  in  an  electric  oven,  for  five  hours 
at  325  deg.  Fahr.  (163  deg.  Cent.)  shall  be  not  more  than  8  per  cent 
and  its  free  carbon  content  shall  not  be  more  than  28  per  cent  nor 
less  than  22  per  cent. 

Specifications  for  Bituminous-treated  Waterproofing  Felt.  The 
felt  must  be  saturated  with  an  approved  asphalt  or  coal-tar  pitch, 
and  must  conform  to  the  following  requirements: 

The  weight  per  100  square  feet  shall  be  from  12  to  15  pounds 
saturated  and  5  to  6  pounds  unsaturated. 

The  saturation  shall  be  thorough  and  complete. 

The  ash  from  the  unsaturated  felt  shall  not  be  less  than  25  per 
cent  by  weight. 

The  wool  in  the  unsaturated  felt  shall  not  be  less  than  10  per 
cent  by  weight. 

Soapstone,  fine  sand,  or  other  substance  on  the  surface  of  the 
felt  to  prevent  adhesion  shall  not  exceed  J  pound  per  100  square  feet 
of  felt. 

The  asphaltic  saturating  compound  and  the  coal-tar  pitch  satu- 
rant  shall  remain  plastic,  at  ordinary  temperatures,  after  being 
heated  to  325  deg.  Fahr.  (163  deg.  Cent.)  for  ten  hours. 


WATERPROOFING  SPECIFICATIONS  265 

Both  the  asphalt-  and  tar-pitch-treated  felts  shall  be  soft,  pliable 
and  tough  when  received  from  the  factory  and  until  placed  in  the 
work. 

The  quotient  obtained  by  dividing  the  tensile  strength  in  pounds, 
of  a  strip  1  inch  wide  cut  lengthwise,  by  the  weight  in  pounds  of 
100  square  feet  shall  not  be  less  than  7,  and,  when  cut  crosswise, 
shall  not  be  less  than  3J. 

The  strength  saturated  shall  be  at  least  25  per  cent  more  than 
the  strength  unsaturated,  taken  lengthwise  (along  the  warp)  and  at 
least  15  per  cent  more  taken  crosswise  (along  the  woof). 

Remarks.  The  above  specification  applies  mainly  to  a  light- 
grade  felt,  such  as  is  commonly  used  for  roofing.  A  wool-content 
of  25  per  cent  produces  the  best  felt,  but  unfortunately  this  has  been 
reduced  to  practically  zero  in  the  ordinary  felts  used  at  the  present 
time.  The  requirements  for  weight  and  strength  called  for  is  readily 
exceeded  by  an  average  good  felt.  Only  the  former,  though,  is 
important,  since  it  is  an  index  of  the  amount  of  preserving  material 
in  the  felt. 

Specifications  for  Bituminous-treated  Jute  Fabric  for  Water- 
proofing. Jute  fabric  for  waterproofing  purposes  shall  be  made  of 
jute  burlap,  saturated  and  coated  with  bitumen,  and  if  necessary 
sprinkled  with  sawdust  to  prevent  adhesion  in  the  roll. 

The  burlap  shall  have  a  trade  weight  rating  of  either  seven  and 
one-half  (7J)  ounces  or  eight  (8)  ounces  per  square  yard  and  shall 
show  a  uniform  open  mesh  with  a  uniform  thickness  of  thread  in 
both  the  warp  and  the  woof. 

The  bitumen  used  for  saturating  and  coating  the  burlap  shall  be 
asphalt  or  coal-tar  or  oil-tar  pitch  meeting  the  following  require- 
ments : 

The  coal-tar  pitch  shall  be  either  a  straight-run  pitch  containing 
not  less  than  25  per  cent,  and  not  more  than  32  per  cent  of  free  carbon ; 
or  an  oil-tar  pitch  containing  not  less  than  10  per  cent  of  free  carbon. 
The  coal-tar  or  oil-tar  pitch  used  as  saturant  shall  melt  at  approxi- 
mately 70  deg.  Fahr.  (21  deg.  Cent.).  The  coal-tar  or  oil-tar  pitch 
used  as  coating  shall  melt  at  approximately  175  deg.  Fahr.  (80  deg. 
Cent.).  The  melting-points  are  to  be  determined  by  the  cube-in- 
water  method. 

The  asphalt  shall  contain  in  its  refined  state  not  less  than  98J 
per  cent  of  bitumen  soluble  in  cold  carbon  tetrachloride.  The 
remaining  ingredients  shall  be  such  as  not  to  exert  an  injurious  effect 
on  the  burlap. 

The  asphalt,  both  saturant  and  coating  shall  not  flash  below 


266  WATERPROOFING  ENGINEERING 

350  deg.  Fahr.  (177  deg.  Cent.)  when  tested  in  the  New  York  State 
Closed  Oil  Tester.  When  heated  in  an  electric  oven  for  five  hours 
at  a  temperature  of  325  deg.  Fahr.  (163  deg.  Cent.)  it  shall  not  lose 
over  two  (2)  per  cent  by  weight,  nor  shall  the  penetration  at  77  deg. 
Fa"hr.  (25  deg.  Cent.)  after  such  heating  be  less  than  one-half  of  the 
original  penetration. 

The  melting-point  of  asphalt  saturant  shall  be  between  100  and 
115  deg.  Fahr.  (38  and  46  deg.  Cent.)  and  of  asphalt  coating,  approxi- 
mately 225  deg.  Fahr.  (107  deg:  Cent.)  as  determined  by  the  Kraemer 
and  Sarnow  method. 

The  consistency  of  the  asphalt  shall  be  determined  by  the  pene- 
tration, which  must  be  between  0.75  and  1.00  cm.  for  the  saturant, 
and  between  0.15  and  0.25  cm.  for  the  coating. 

A  briquette  of  the  saturant  of  a  cross-section  of  1  sq.  cm.  shall 
have  a  ductility  of  not  less  than  fifty  (50)  centimeters  and  of  the 
coating  not  less  than  five  (5)  cm.  at  77  deg.  Fahr.  on  a  Smith  ductility 
machine. 

All  tests  herein  specified  must  be  conducted  according  to  methods 
approved  by  the  engineer. 

The  very  fine  sawdust  shall  be  a  granulated  cedar,  pine,  or  other 
suitable  wood,  and  applied  on  one  side  of  the  fabric  so  that  not 
more  than  5  ounces  will  cover  100  square  feet. 

The  burlap  shall  be  thoroughly  dried  before  being  saturated; 
it  shall  be  thoroughly  saturated  and  coated  with  bitumen,  but 
shall  retain  between  30  and  40  per  cent  of  the  open  mesh  of  the  un- 
treated burlap.  The  fabric  after  treatment  shall  be  pliable  without 
flaking  at  all  working  temperatures  after  treatment. 

The  temperature  of  the  saturant  and  coating  materials  during 
the  process  of  treating  the  fabric  shall  not  exceed  300  deg.  Fahr. 
(149  deg.  Cent.). 

The  machinery  and  method  of  saturating  and  coating  the  burlap 
shall  be  subject  to  the  approval  of  the  engineer. 

The  treated  fabric  shall  have  a  tensile  strength  in  the  direction 
of  its  length  (warp)  of  not  less  than  eighty  (80)  pounds  and  in  the 
direction  of  its  width  (woof) ,  not  less  than  sixty  (60)  pounds  per  lineal 
inch  of  test  specimen. 

The  fabric,  when  examined  under  a  magnifying  glass,  shall  show 
the  inner  strands  to  be  actually  saturated  and  the  outer  strands  well 
coated.  A  piece  of  fabric  ripped  along  a  line  diagonal  to  the  warp 
and  the  woof  shall  show  thorough  saturation  of  the  strands.  The 
percentage  of  open  mesh  may  be  approximated  by  holding  a  large 
piece  of  fabric  before  a  light. 


WATERPROOFING  SPECIFICATIONS  267 

The  finished  fabric  shall  weigh  not  less  than  two  and  one-half 
times  nor  more  than  three  and  one-half  (3J)  times  the  weight 
of  the  raw  burlap. 

The  finished  roll  of  fabric  shall  unroll  easily.  The  completed 
fabric  shall  be  wound  on  a  core  or  spool  of  wood,  fiber  or  other  strong 
material,  not  less  than  two  (2)  inches  in  its  smallest  dimension,  and 
equal  in  length  to  the  width  of  the  fabric. 

The  fabric  shall  be  delivered  in  rolls  not  exceeding  one  hundred 
seventy-five  (175)  feet  in  length.  The  width  shall  not  be  less  than 
three  (3)  feet.  The  shrinkage  due  to  saturation  shall  not  exceed 
two  (2)  per  cent.  When  the  fabric  is  brought  on  the  work  it  shall  be 
stored  in  a  dry  and  cool  place,  piled  no  more  than  four  rolls  high, 
never  stood  on  ends,  and  protected  against  rain  and  other  weather 
conditions  as  well  as  from  injury  from  resting  or  falling  weights. 

Remarks.  The  above  specifications  are  probably  the  most  com- 
plete of  their  type.  Fabric  made  according  to  them  has  been  used 
very  extensively  and  very  successfully  on  the  New  York  Subway 
System.  Engineers  sometimes  contend  that  it  is  unnecessary  to 
saturate  and  coat  burlap,  arguing  that  the  bituminous  binder  applied 
on  the  work  is  sufficient  to  protect  it.  Experience  has  proven  that 
saturation  and  coating  of  the  fabric  is  essential  for  best  results. 
The  practice  of  applying  untreated  burlap,  never  very  extensive, 
is  gradually  being  abandoned. 

Specifications  for  Asphalt  for  Waterproofing  or  Dampproofing.* 
These  specifications  cover  asphalt  for  waterproofing  and  damp- 
proofing  recommended  for  use  under  uniformly  moderate  tempera- 
ture conditions. 

The  melting-point  shall  be  between  100  and  140  deg.  Fahr.  (38 
and  60  deg.  Cent.)  as  determined  by  the  ball-and-ring  method, 
and  shall  be  specified  for  one  of  the  following  classes:  130  to  140 
deg.  Fahr.  (54.5  to  60  deg.  Cent.);  115  to  130  deg.  Fahr.  (46  to  54.5 
deg.  Cent.);  100  to  115  deg.  Fahr.  (38  to  46  deg.  Cent.). 

The  penetration  at  77  deg.  Fahr.  (25  deg.  Cent.),  under  a  load  of 
100  grams  for  5  seconds,  shall  be  not  less  than  50  nor  more  than 
125. 

The  penetration  shall  bear  the  following  relation  to  the  melting- 
point:  Penetration  of  50  to  75  for  melting-points  between  130  and 
140  deg.  Fahr.  Penetration  of  75  to  100  for  melting-points  between 
115  and  130  deg.  Fahr.  Penetration  of  100  to  125  for  melting- 
points  between  100  and  115  deg.  Fahr. 

*  Proposed  tentative  specifications,  Proceedings  American  Society  for  Test- 
ing Materials,  Vol.  17,  pp.  712-722  (1917). 


268  WATERPROOFING  ENGINEERING 

The  ductility  at  77  deg,  Fahr.  (25  deg.  Cent.),  when  a  briquette 
of  the  material  having  a  minimum  cross-section  of  1  sq.  cm.  is  pulled 
apart  at  the  rate  of  5  cm.  per  minute,  shall  not  be  less  than  30  cm. 

The  specific  gravity  shall  not  be  more  than  1.08  at  77/77  deg. 
Fahr.  (25/25  deg.  Cent.). 

The  bitumen  soluble  in  cold  carbon  bisulphide  shall  not  be  less 
than  95  per  cent. 

The  loss  of  a  50-gram  sample  on  heating  at  325  deg.  Fahr.  (163 
deg.  Cent.),  for  five  hours,  shall  not  exceed  1  per  cent.  The  pene- 
tration of  the  residue  from  this  test  shall  not  be  less  than  50  per  cent 
of  the  original  penetration. 

The  ash  shall  not  exceed  4  per  cent. 

Specifications  for  Primer  for  Use  with  Asphalt  for  Waterproofing 
or  Dampproofing.*  These  specifications  cover  primer  for  use  when 
specified  with  asphalt  for  waterproofing  or  dampproofing. 

The  primer  shall  consist  of  an  asphaltic  base,  complying  in 
every  respect  with  the  specifications  of  asphalt  for  waterproofing 
below  grade  (page  267),  which  shall  be  thinned  to  ordinary  paint 
consistency  with  a  petroleum  distillate  having  an  end  point  on 
distillation  not  above  500  deg.  Fahr.  (260  deg.  Cent.).  Not  more 
than  20  per  cent  of  this  petroleum  distillate  shall  distill  under 
248  deg.  Fahr.  (120  deg.  Cent.). 

Specifications  for  Asphalt  for  Waterproofing  Surface  and  Sub- 
surface Structures.!  Asphalt  shall  be  used  which  is  of  the  best  grade, 
free  from  coal  tar  or  any  of  its  products,  and  which  will  not  volatilize 
more  than  \  of  1  per  cent  under  a  temperature  of  325  deg.  Fahr. 
(163  deg.  Cent.)  for  seven  hours. 

It  must  not  be  affected  by  a  20  per  cent  solution  of  ammonia, 
a  25  per  cent  solution  of  sulphuric  acid,  a  35  per  cent  solution  of 
muriatic  acid,  nor  by  a  saturated  solution  of  sodium  chloride.  It 
should  show  no  hydrolytic  decomposition  when  subjectec »..  for  a  period 
of  ten  hours,  to  hourly  immersions  in  water  with  alternate  rapid 
dryings  by  warm  air  currents. 

For  metallic  structures,  exposed  to  the  direct  rays  of  the  sun, 
the  asphalt  must  not  flow  under  200  deg.  Fahr.  (93.5  deg.  Cent.), 
nor  become  brittle  at  0  deg.  Fahr.  (  —  17.7  deg.  Cent^  /vhen  spread 
on  thin  glass. 

For  structures  under  ground,  such  as  masonry  arcl  53,  abutments, 
retaining  walls,  foundation  walls  of  buildings,  subways,  etc.,  a  flow 

*  Proposed  tentative  specifications,  Proceedings  American  Society  for  Testing 
Materials,  Vol.  17,  Part  1,  pp.  712-722  (1917). 
f  Chicago  &  Northwestern  Railway  Company. 


WATERPROOFING  SPECIFICATIONS  269 

point  of  180  deg.  Fahr.  (82  deg.  Cent.)  and  a  brittle  point  of  0  deg. 
Fahr.  will  be  required. 

A  mastic  made  from  either  grade  of  asphalt  by  mixing  it  with 
sand  in  the  proportion  of  1  of  asphalt  to  4  of  sand,  must  not  percepti- 
bly indent,  when  at  a  temperature  of  130  deg.  Fahr.  (54.5  deg.  Cent.) 
under  a  load  of  20  pounds  per  square  inch.  It  must  also  remain 
pliable  at  a  temperature  of  0  deg.  Fahr. 

Remarks.  It  may  be  noted  that  the  above  specifications  call 
mainly  for  physical  tests.  The  kind  of  asphalt  specified  must 
necessarily  be  fluxed,  as  neither  natural  nor  artificial  asphalts  can, 
of  themselves,  meet  the  above  requirements.  Yet  the  few  tests  called 
for  are  undoubtedly  sufficient  to  guarantee  the  quality  of  the  asphalt, 
for  the  loss  on  heating  test  limits  the  amount  and  grade  of  fluxing 
material,  and  the  flow  point  and  brittle  point  requirement  limits 
the  grade  and  quality  of  the  original  asphalt.  Unless  both  of  these 
materials  are  of  the  proper  consistenty  and  properly  blended,  the 
results  of  the  tests  would  not  check  with  the  requirements.  The 
test  requirements  of  the  aboye  specifications  are  a  material  departure 
from  the  almost  standard  requirements  for  waterproofing  asphalts, 
which  usually  call  for  a  melting-point  test,  loss  on  heating,  solubility 
in  carbon  bisulphide  or  carbon  tetrachloride,  solubility  in  petrolic 
ether,  penetration,  ductility,  and  specific  gravity. 

In  the  flow-point  test  requirement,  a  time  limit  should  be  speci- 
fically stated,  as  also  in  the  indent  test  for  mastic,  because  neither 
the  asphalt  nor  the  mastic  will  fulfill  the  requirements  in  unlimited 
time.  It  would  seem,  though,  that  one  of  the  so-called  melting- 
point  tests  would  be  better  to  use  then  the  flow-point  test  because 
the  function  of  the  latter  is  primarily  to  show  the  relative  flowing 
properties  of  bituminous,  and  besides,  it  is  not  extensively  used  in 
the  industry. 

Specifications  for  Coal-tar  Pitch  for  Waterproofing  and  Damp- 
proofing.*  These  specifications  cover  coal-tar  pitch  for  waterproofing 
and  dampproofing  recommended  for  use  under  uniformly  moderate 
temperature  conditions. 

The  melting-point  as  determined  by  the  cube-in- water  method, 
shall  be  between  120  and  140  deg.  Fahr.  (49  and  60  deg.  Cent.). 
In  specifying  the  melting-point  desired  within  the  above  limits,  a 
variation  of  not  more  than  5  deg.  Fahr.  (2.5  deg.  Cent.)  in  either 
direction  will  be  permitted. 

The  penetration  at  77  deg.  Fahr.  (25  deg.  Cent.),  under  a  load  of 

*  Proposed  tentative  specifications,  Proceedings  American  Society  for  Testing 
Materials,  Vol.  17,  Part  1,  pp.  712-722  (1917). 


270  WATERPROOFING  ENGINEERING 

100  grams  for  five  seconds  shall   not  be  less  than  20  nor  more 
than  120. 

The  ductility,  at  77  deg.  Fahr.  when  a  briquette  of  the  material 
having  a  minimum  section  of  1  sq.  cm.  is  pulled  apart  at  the  rate 
of  5  cm.  per  minute  shall  not  be  less  than  40  cm. 

The  loss  of  a  20-gram  sample  on  heating  at  325  deg.  Fahr.  (163 
deg.  Cent.)  for  five  hours  on  pitch  of  melting-point  between  120  and 
130  deg.  Fahr.  (49  and  54.5  deg.  Cent.)  shall  not  exceed  9  per  cent, 
and  on  pitch  of  melting-point  between  130  and  140  deg.  Fahr.  (54.5 
and  60  deg.  Cent.)  shall  not  exceed  7  per  cent. 

The  specific  gravity  of  the  pitch  at  77/77  deg.  Fahr.  (25/25  deg. 
Cent.)  shall  not  exceed  the  limits  of  1.24  and  1.34. 

The  specific  gravity  at  140/140  deg.  Fahr.  (60/60  deg.Cent.)  of  the 
distillate  to  671  deg.  Fahr.  (355  deg.  Cent.)  shall  not  be  less  than  1.06. 

The  matter  soluble  in  hot  toluol-benzol  shall  not  be  less  than  65 
nor  more  than  85  per  cent. 

The  ash  shall  not  exceed  1  per  cent. 

Specifications  for  Creosote  Oil  for  Priming  Coat  with  Coal-tar 
Pitch  for  Waterproofing  and  Dampproofing.*  When  it  is  specified 
that  previous  to  the  mopping  on  of  the  hot  coal-tar  pitch,  the  wall, 
floor,  or  foundation,  shall  be  painted  with  a  priming  coat,  the  following 
specifications  for  creosote  oil  shall  apply: 

Creosote  oil  shall  be  of  pure  tar  distillate,  free  from  any  sub- 
stance foreign  to  a  tar  distillate. 

The  oil  shall  be  entirely  fluid  at  100  deg.  Fahr.  (38  deg.  Cent.). 

The  specific  gravity  at  100  deg.  Fahr.  shall  not  be  less  than  1.00 
nor  more  than  1.06. 

Insoluble  matter  in  hot  benzol  shall  be  less  than  1  per  cent. 

When  distilled,  it  shall  yield:  (a)  water  not  more  than  2  per  cent; 
(b)  not  more  than  5  per  cent  shall  distill  under  392  deg.  Fahr.  (200 
deg.  Cent.);  (c)  not  more  than  50  nor  less  than  30  per  cent  shall 
distill  under  455  deg.  Fahr.  (235  deg.  Cent.) :  (d)  the  residue  above 
671  deg.  Fahr.  (355  deg.  Cent.)  shall  not  exceed  15  per  cent;  (e) 
the  residue  shall  be  soft;  (/)  the  specific  gravity  at  100  deg.  Fahr. 
(38  deg.  Cent.)  of  the  fraction  distilling  between  455  and  599  deg. 
Fahr.  (235  and  315  deg.  Cent.),  shall  not  be  less  than  1.00. 

Coal-tar  Pitch  for  Mastic  Waterproofing.  Coal-tar  pitch  in- 
tended for  mastic  for  brick-in-mastic  waterproofing  shall  be  a 
straight-run  residue  obtained  from  the  distillation  of  coal  tar  and 
shall  meet  the  following  requirements- 

*  Proposed  tentative  specifications,  Proceedings  American  Society  for  Testing 
Materials,  Vol.  17,  Part  1,  pp.  712-722  (1917). 


WATERPROOFING  SPECIFICATIONS 


271 


The  melting-point  shall  be  not  less  than  116  nor  more  than  122 
deg.  Fahr.  (47  and  50  deg.  Cent.),  determined  by  the  cube-in-water 
method.  The  penetration  (Dow  machine)  at  77  deg.  Fahr.  (25 
deg.  Cent.)  with  100  grams  acting  for  five  seconds,  shall  be  not 
more  than  180  and  not  less  than  110. 

The  matter  insoluble  in  hot  extraction  in  benzol  and  toluol  shall 
be  not  less  than  24  and  not  more  than  32  per  cent. 

The  ash  shall  not  exceed  1  per  cent. 

On  distillation  to  671  deg.  Fahr.  (355  deg.  Cent.),  the  specific 
gravity  of  the  total  distillate  shall  be  not  less  than  1.06,  determined 
at  140/140  deg.  Fahr.  (60/60  deg.  Cent.). 

Remarks.  Coal-tar  pitch  meeting  the  above  specifications  has 
not  yet  been  used  for  making  waterproofing  mastic.  In  fact,  no 
coal-tar  pitch  has  ever  been  used  for  the  purpose  mentioned  in  the 
specifications,  because  it  was  always  considered  impossible  to  obtain 
a  tar-pitch  that  would  be  at  all  plastic  at  32  deg.  Fahr.  (0  deg.  Cent.). 
But  as  a  result  of  extensive  tests  a  grade  of  pitch  has  been  evolved  in 
which  this  objection  has  been  overcome.  The  above  specification 
is  based  on  that  series  of  tests.  The  method  of  making  mastic  is 
explained  in  Chapter  II. 

Hydrated  Lime  for  Integral  Waterproofing.*  Hydrated  lime  is 
a  dry  flocculent  powder  resulting  from  the  hydration  of  quicklime. 
It  is  commercially  divided 'into  four  classes:  (a)  High  calcium; 
(6)  calcium;  (c)  magnesian;  (d)  high-magnesian. 

The  classes  and  chemical  properties  of  hydrated  lime  shall  be 
determined  by  standard  methods  of  chemical  analysis. 

The  non- volatile  portion  of  hydrated  lime  shall  conform  to  the 
following  requirements  as  to  chemical  composition : 

CHEMICAL  COMPOSITION  OF   HYDRATED   LIME 


Properties  Considered. 

High  Calcium. 

Calcium. 

Magnesian. 

High 
Magnesian, 

Calcium  oxide.  ..... 

Per  Cent. 

90  (min.) 

Per  Cent. 

85-90 

Per  Cent. 

Per  Cent. 

Magnesian  oxide 

10-25 

5 
5 
Sufficient  to 
hydrate   the 
calcium-oxide 
content. 

25  (min.) 

5 
5 
Sufficient  to 
hydrate   the 
calcium-oxide 
content. 

Silica    alumina    oxide 
of  iron  (max.)     
Carbon  dioxide  (max.).  . 
Water.    . 

5 
5 
Sufficient  to 
hydrate   the 
calcium-oxide 
content. 

5 
5 
Sufficient  to 
hydrate   the 
calcium-oxide 
content. 

Book  of  American  Society  for  Testing  Materials  Standards,  p.  472,  1916. 


272  WATERPROOFING  ENGINEERING 

A  100-gram  sample  shall -leave  by  weight  a  residue  of  not  over 
five  (5)  per  cent  on  a  standard  100-mesh  sieve  and  not  over  0.5  per 
cent  on  a  standard  30  mesh-sieve. 

Hydrated  lime  shall  be  tested  to  determine  its  constancy  of 
volume  in  the  following  manner : 

Equal  parts  of  the  hydrated  lime  under  test  and  volume-con- 
stant Portland  cement  shall  be  thoroughly  mixed  together  and 
gaged  with  water  to  a  paste.  Only  sufficient  water  shall  be  used 
to  make  the.  mixture  workable.  From  this  paste  a  pat  about  3 
inches  in  diameter  and  J  inch  thick  at  the  center,  tapering  to  a  thin 
edge  shall  be  made  on  a  clean  glass  plate  about  4  inches  square. 
This  pat  shall  be  allowed  to  harden  twenty-four  hours  in  moist 
air  and  shall  be  without  popping,  checking,  cracking,  warping  or 
disintegration  after  five  hours'  exposure  to  steam  above  boiling  water 
in  a  loosely  closed  vessel. 

The  sample  shall  be  a  fair  average  of  the  shipment.  Three  per 
cent  of  the  packages  shall  be  sampled.  The  sample  shall  be  taken 
from  the  surface  to  the  center  of  the  package.  A  2-pound  sample  to 
be  sent  to  the  laboratory  shall  immediately  be  transferred  to  an  air- 
tight container,  in  which  the  unused  portion  shall  be  stored  until 
the  hydrated  lime  has  been  finally  accepted  or  rejected  by  the 
purchaser. 

Hydrated  lime  shall  be  packed  eitfier  in  cloth  or  in  paper  bags 
and  the  weight  shall  be  plainly  marked  on  each  package. 

The  name  of  the  manufacturer  shall  be  legibly  marked  or  tagged 
on  each  package. 

All  hydrated  lime  shall  be  subject  to  inspection. 

The  hydrated  lime  may  be  inspected  either  at  the  place  of  manu- 
facture or  the  point  of  delivery,  as  arranged  at  the  time  of  purchase. 

The  inspector  representing  the  purchaser  shall  have  free  entry 
at  all  times  while  work  on  the  contract  of  the  purchaser  is  being  per- 
formed, to  all  parts  of  the  manufacturer's  works  which  concern  the 
manufacture  of  the  hydrated  lime  ordered.  The  manufacturer  shall 
afford  the  inspector  all  reasonable  facilities  for  inspection  and 
sampling,  which  shall  be  so  conducted  as  not  to  interfere  unneces- 
sarily with  the  operation  of  the  works. 

The  purchaser  may  make  the  tests  to  govern  the  acceptance  or 
rejection  of  the  hydrated  lime  in  his  own  laboratory  or  elsewhere. 
Such  tests,  however,  shall  be  made  at  the  expense  of  the  purchaser. 

Unless  otherwise  specified,  any  rejection  based  on  failure  to 
pass  tests  prescribed  in  these  specifications  shall  be  reported  within 
five  working  days  from  the  taking  of  samples. 


WATERPROOFING  SPECIFICATIONS  273 

Samples  which  represent  rejected  hydra  ted  lime  shall  be  pre- 
served in  airtight  containers  for  five  days  from  the  date  of  the  test 
report.  In  case  of  dissatisfaction  with  the  results  of  the  tests,  the 
manufacturer  may  make  claim  for  a  rehearing  within  that  time. 

Remarks.  The  above  specifications  will  be  of  material  aid  to 
the  architect  and  engineer  in  obtaining  a  product  dependably  suit- 
able forjwaterproofing  by  the  integral  method.  Though  it  is  claimed 
that  there  is  little  or  no  difference  which  grade  of  hydrated  lime  is 
used,  still,  the  following  facts  have  positively  been  ascertained: 
The  high  magnesian  lime  (25  to  40  per  cent  magnesia)  though  it 
slakes  and  sets  more  slowly,  takes  up  less  water,  generates  less  heat 
and  expands  and  shrinks  less  than  the  high  calcium  lime;  also  that 
even  ordinary  magnesian  lime  (5  to  25  per  cent  magnesia)  works 
more  smoothly  and  though  it  also  sets  slower,  it  is  stronger  than  high* 
calcium  lime. 

SPECIFICATIONS  FOR  WATERPROOFING  CONCRETE  AND  MASONRY 

STRUCTURES 

Specifications  for  Dampproofing  Concrete  with  Coal  Tar.     The 

concrete  surface  to  be  dampproofed  should  be  smooth,  thoroughly 
clean  and  dry.  The  entire  surface  should  be  mopped  with  a  coating 
of  dead  oil,  using  all  that  the  concrete  will  absorb.  If  applied  in 
cold  weather,  the  dead  oil  should  be  heated;  in  hot  weather  it  can 
be  applied  cold. 

The  dead  oil  should  conform  to  the  Specifications  for  Creosote 
Oil  for  Priming  Coat  with  Coal-tar  Pitch  for  Waterproofing  and 
Dampproofing,  page  270. 

When  the  entire  surface  is  completely  mopped  with  the  dead  oil, 
it  should  be  remopped  with  a  straight-run  coal-tar  pitch,  following 
same  with  additional  moppings  until  the  whole  surface  has  a  bright, 
patent-leather  appearance.'  The  coal-tar  pitch  should  conform  to 
the  Specification  for  Coal-tar  Pitch  for  Waterproofing  and  Damp- 
proofing,  page  269. 

Both  the  dead  oil  and  the  coal-tar  pitch  must  be  delivered  on  the 
work  in  packages  that  are  plainly  marked  with  the  manufacturer's 
brand,  and  indicating  the  grade  and  quality  of  the  material. 

Waterproofing  Flat  Concrete  Surfaces  with  Coal-tar  Pitch  Mastic. 
The  mastic  shall  consist  of  gravel,  sand  and  coal-tar  pitch.  The 
materials  shall  be  mixed  together  in  the  proportion  of  three  parts  of 
gravel,  two  parts  of  sand,  and  one  part  of  coal-tar  pitch  by  volume. 
The  sand  and  gravel  shall  be  thoroughly  dried,  and  all  materials 


274  WATERPROOFING  ENGINEERING 

heated  sufficiently  to  permit  thorough  mixing,  but  in  no  case  shall  the 
temperature  exceed  300  deg.  Fahr.  (149  deg.  Cent.). 

The  gravel  shall  be  from  f  to  f  inch  in  size. 

The  sand  shall  pass  100  per  cent  through  an  8-mesh  sieve. 

The  pitch  shall  have  a  melting-point  of  about  125  deg.  Fahr. 
(52  deg.  Cent.)  by  the  cube-in-water  method. 

The  mixture  shall  be  spread  over  the  surface  to  the  required  thick- 
ness, compacted  either  by  tamping  or  rolling,  and  given  a  mopping 
of  coal-tar  pitch  the  same  as  is  used  in  the  mixture. 

If  ballast  is  to  be  applied  directly  on  the  mastic,  the  latter  should 
be  2  inches  thick.  If  there  is  sufficient  space  to  allow  for  a  sand 
cushion  above  the  mastic,  1J  inches  of  mastic  is  sufficient. 

Remarks.  The  above  specifications  are  concise  but  somewhat 
incomplete.  By  specifying  a  |-inch  (maximum  size)  gravel;  the  in- 
corporation of  at  least  one  part  cement  or  limestone  dust  in  place 
of  one  of  the  parts  of  gravel;  and  more  test  requirements  for  the 
pitch,  such  as  free  carbon  content,  specific  gravity  of  distillate  oils 
and  penetration  (which  would  permit  identification  of  the  pitch  on 
the  work),  a  more  certain  grade  of  mastic  would  result. 

Specifications  for  Waterproofing  Concrete  Structures  by  the 
Integral  Method.  Watertightness  shall  be  secured  by  the  addition 
of  A  *  into  the  mass  or  by  plastering  or  veneering  the  interior  or 
exterior  of  the  structure  with  a  continuous  coat  of  waterproofed 
cement  mortar. 

Concrete  should  consist  of  one  (1)  part  of  cement,  two  (2)  or  three 
(3)  parts  of  sand  and  four  (4)  or  five  (5)  parts  of  stone  each  to  meet 
standard  requirements.  The  quantity  of  A  to  be  used  is  8  to  16 
pounds  per  cubic  yard  of  puddled  concrete.  Introduce  the  water- 
proofing at  the  mixer,  by  mixing  it  into  water  first. 

Placing  of  concrete  shall  be  continuous  throughout  definite 
stages  and  joints  between  different  days'  work  shall  be  carefully 
treated  to  obtain  positive  bond. 

Cement  mortar  shall  be  prepared  by  thoroughly  tempering  a  dry 
mixture  of  one  (1)  part  of  cement  to  either  two  (2)  or  three  (3)  parts 
of  sand  with  water  to  which  A  has  been  added  as  follows : 

Under  ordinary  conditions  10  pounds  per  cubic  yard  of  mortar; 
permanent  ground  water,  16  to  24  pounds  per  cubic  yard  of  mortar; 
ground  water  pressure,  up  to  32  pounds  per  cubic  yard  of  mortar; 
the  mortar  to  be  \  to  1  inch  thick. 

The  continuous  cement  coat  must  be  applied  in  several  layers 

*  These  specifications  are  for  the  use  of  a  proprietary  calcium-oleate  com- 
pound, herein  designated  by  A. 


WATERPROOFING  SPECIFICATIONS  275 

after  the  underlying  concrete  has  been  cleansed  of  dust  and  dirt. 
The  concrete  surface  should  be  washed  with  a  10  per  cent  solution 
of  acid  water  and  afterward  rewashed  thoroughly  with  clear  water 
to  remove  the  acid. 

The  prime  or  scratch  coat  is  to  be  well  troweled. 

The  final  coat  must  be  floated  with  a  wooden  or  cork  float  to 
avoid  air-cushions.  The  work  is  to  be  protected  against  the  rays  of 
the  sun  or  in  winter  against  freezing. 

Keep  mortar  damp  so  as  to  prevent  too  rapid  drying. 

Remarks.  The  above  specifications  are  cited  merely  because 
they  are  typical  of  many  of  those  issued  for  proprietary  integral 
waterproofing  compounds.  It  is  explicit  enough,  but  since  no  state- 
ment of  composition  or  properties  of  the  waterproofing  compound 
is  included,  what  may  be  expected  of  the  use  of  the  material  depends 
upon  the  integrity  of  the  manufacturers.  In  Chapters  II  and  X 
will  be  found  information  which  should  be  consulted  before  the  above 
type  of  specifications  are  accepted  as  a  model  by  the  architect  or 
engineer. 

Specifications  for  Waterproofing  Concrete  and  Masonry  Struc- 
tures by  the  Integral-mortar  Surface  Coating  Method.  It  is  the 
intent  of  these  specifications  to  obtain  a  watertight  structure. 

Watertightness  shall  be  secured  by  plastering  the  interior  sur- 
face of  the  structure  with  a  continuous  coat  of  Portland  cement 
mortar  waterproofed  with  B  *  waterproofing  paste. 

The  mortar  composing  the  plaster  coat  shall  consist  of  one  (1) 
part  of  cement  and  two  (2)  parts  of  sand,  to  meet  the  following 
requirements: 

The  cement  shall  be  a  high-grade  Portland,  which  has  been  care- 
fully tested  and  found  to  satisfactorily  meet  the  requirements  of  the 
Standard  Specifications  of  the  American  Society  for  Testing  Materials 
and  preferably  ground  so  that  eighty  per  cent  (80%)  shall  pass  a 
standard  two  hundred  (200) -mesh  sieve. 

The  sand  shall  consist  of  spherical  grains  of  any  hard  rock  that 
is  practically  free  from  clay,  absolutely  free  from  organic  matter, 
and  uniformly  graded  in  size  from  coarse  to  fine. 

The  waterproofed  cement  mortar  shall  be  prepared  by  thoroughly 
tempering  (to  required  consistency)  a  dry  mixture  of  one  (1)  part  of 
cement  and  two  (2)  parts  of  sand,  with  water  to  which  B  waterproof- 
ing paste  has  been  added  in  the  proportion  of  one  (1)  part  of  paste 
to  eighteen  (18)  parts  of  water,  as  directed  by  the  manufacturer. 

*  These  specifications  are  for  the  use  of  a  proprietary  alum-soap  paste 
compound,  herein  designated  by  B. 


276  WATERPROOFING  ENGINEERING 

Before  plastering  the  cement  mortar  on  the  hardened  concrete, 
the  surface  of  same  shall  be  treated  as  indicated  in  the  following: 

The  hardened  surface  shall  be  mechanically  roughened  by  chip- 
ping and  very  thoroughly  cleaned  with  a  heavy  wire  broom,  so  as  to 
remove  all  dust  and  dirt.  A  jet  of  steam  shall  be  employed  to  clean 
the  wall,  if  available. 

To  the  mechanically  cleaned  surface  apply  with  a  large  acid 
brush,  a  liberal  coat  of  one  to  ten  (1  :  10)  solution  of  hydrochloric 
acid  (muriatic  acid) .  Allow  the  acid  to  remain  until  it  has  exhausted 
itself,  which  will  require  at  least  ten  minutes.  Apply  a  second  coat 
of  acid  solution. if  the  first  does  not  sufficiently  clean  and  expose 
the  surface  of  the  aggregate. 

With  a  hose  under  good  pressure,  slush  the  surface  so  as  to  remove 
the  salts  and  loose  particles  resulting  from  the  action  of  the  acid. 
Continue  the  slushing  until  the  old  concrete  is  thoroughly  cleaned  and 
soaked  to  its  full  capacity.  Thoroughly  wire-brush  the  surface  so 
as  to  remove  the  particles  which  have  been  loosened  by  the  action 
of  the  acid. 

To  the  cleaned  saturated  surface  apply  with  a  strong  fiber  brush 
a  coating  of  pure  cement  mixed  to  a  thick  creamy  consistency  with 
water  to  which  B  waterproofing  paste  has  been  added  in  the  pro- 
proportion  of  one  (1)  part  of  paste  to  eighteen  (18)  parts  of  water. 
Rub  in  vigorously  so  as  to  fill  all  crevices  and  cavities  produced  by 
the  action  of  the  acid. 

Immediately  after  applying  the  above  slush  coat,  the  first  coat 
of  waterproofed  cement  mortar  shall  be  applied  to  a  thickness  of 
three-eighths  (f)  of  an  inch  directly  on  the  slush  coat,  and  well 
troweled  and  rubbed  into  the  crevices  of  the  surface.  This  first 
coat  shall  be  lightly  scratched  before  showing  initial  set.  Before 
this  first  coat  has  reached  its  final  set,  the  second  coat  shall  be  applied, 
of  equal  thickness,  so  as  to  give  a  full  average  thickness  of  three- 
quarters  (|)  of  an  inch.  Special  care  shall  be  exercised  to  apply 
this  finish  coat  before  the  first  coat  has  reached  its  final  set.  The 
finish  coat  shall  be  thoroughly  floated  to  an  even  surface  and  sub- 
sequently troweled  free  from  any  porous  imperfections. 

Where  water  is  running  through  the  wall,  proper  drainage  must 
be  provided  by  drilling  holes  and  inserting  tubes  in  the  wall,  to  con- 
centrate the  flow  of  water.  With  the  pressure  relieved,  the  water- 
proofed plaster  coat  shall  be  applied  to  the  drained  portions  of  the 
wall.  The  drainage  pipes  shall  remain  open  until  the  waterproofed 
plaster  coat  has  thoroughly  set  and  is  capable  of  resisting  the  pressure 
by  its  own  adhesive  strength,  when  the  drainage  pipes  shall  be  closed 


WATERPROOFING  SPECIFICATIONS  277 

with  suitable  plugs  and  coated  with  the  waterproofed  cement 
mortar. 

The  floors  shall  be  prepared  and  treated  exactly  as  indicated 
above,  and  finished  with  a  waterproof  cement  mortar  to  a  thickness 
of  two  (2)  inches.  Special  care  should  be  exercised  to  bond  the  wall 
coating  to  the  floor  coating,  so  as  to  make  the  waterproofed  coating 
continuous  over  the  entire  surface. 

When  hardened,  the  waterproofed  plaster  coat  shall  be  sounded 
with  a  light  hammer  and  all  loose  and  defective  plaster  shall  be  cut 
out  and  replaced. 

Remarks.  Consistent  with  proprietary  waterproofing  materials 
specifications  the  one  above  does  not  mention  anything  about  the 
property  or  quality  of  the  compound  specified.  Neither  is  there 
included  a  guarantee  that  the  application  of  this  material  will  make 
a  watertight  job  for  any  period  of  time.  On  small  or  unimportant 
work,  the  engineer  or  architect  may  permit  waterproofing  under 
the  above  type  of  specifications,  but  for  large  or  difficult  work 
careful  investigation  and  technical  and  practical  tests  are  essential. 
This  procedure  would  undoubtedly  tend  toward  final  economy  and 
more  certainty  of  results. 

Specifications  for  Waterproofing  Cement  Stucco  by  the  Integral 
Method.  The  materials  composing  the  stucco  should  consist  of: 
Twelve  parts  clean  sharp  sand;  one  part  hydrated  lime;  five  parts 
standard  Portland  cement. 

The  waterproofing  paste  *  should  be  mixed :  One  part  water- 
proofing paste;  eighteen  parts  water. 

The  paste  should  be  dissolved  in  one  part  of  water  to  insure  a 
perfect  blending,  after  which  add  the  other  seventeen  parts  water 
and  stir  until  smooth. 

The  cement  and  hydrated  lime  should  be  mixed  to  a  uniform 
color,  before  sand  is  added,  then  add  sand  and  mix  again  to  a  uniform 
color,  after  which  add  the  waterproofed  water,  or  "  milk  "  obtained 
as  per  preceding  paragraph.  This  mortar  must  be  well  "  worked  " 
and  applied  immediately.  No  mortar  should  be  used  after  standing 
more  than  thirty  minutes. 

All  stucco  should  be  two-coat  work.  The  first  coat  should  be 
mixed  as  above  with  the  addition  of  sufficient  long  cow  hair  for  key- 
ing, when  applied  to  metal  lathe.  If  on  masonry,  the  surface  must 
be  saturated  with  water  before  applying  and  the  plaster  applied  before 
base  is  dry. 

*  The  waterproofing  paste  referred  to  in  these  specifications  is  a  quasi-soap 
or  quasi-colloidol  paste. 


278  WATERPROOFING  ENGINEERING 

After  the  first  coat  has  been  applied  it  should  be  roughened  so 
as  to  form  a  base  for  keying  the  finishing  coat,  which  must  be  floated 
in  order  to  densify  the  plaster. 

The  finished  stucco  must  be  kept  wet  for  four  or  five  days  by 
covering  with  burlap  or  other  suitable  material  and  sprinkled  at 
least  twice  a  day. 

Remarks.  The  remarks  appended  to  the  preceding  specifica- 
tions also  apply  here.  The  hydrated  lime  called  for  in  this  speci- 
tion  is  of  itself  an  efficient  waterproofing  agent. 

Specifications  for  Waterproofing  Foundations  by  the  Membrane 
System.  The  foundation  shall  be  waterproofed,  so  that  the  interior 
will  be  permanently  free  from  moisture,  by  a  continuous  sheet  of 
waterproofing  surrounding  the  exterior  and  bottom  to  the  height 
directed  by  the  engineer. 

The  surface  of  all  masonry  upon  which  the  waterproofing  is  to 
be  applied  shall  be  comparatively  smooth  and  as  dry  as  is  practic- 
able. 

Coat  the  entire  surface  on  which  the  waterproofing  is  to  be  applied 
with  tar  pitch,*  into  which,  while  hot,  imbed  a  layer  of  treated  felt,f 
following  this  with  alternating  layers  of  felt  and  pitch  until  five 
layers  of  felt  and  six  moppings  of  pitch  have  been  applied.  All  felt 
must  be  bedded  into  the  pitch  while  the  latter  is  still  hot  but  in  no 
place  shall  felt  touch  felt. 

At  all  wall  angles,  corners  and  any  place  'where  in  the  opinion  of 
the  engineer  the  waterproofing  course  will  be  subjected  to  unusual 
strain,  there  shall  also  be  used  one  layer  of  reinforced  felt  t  and  an 
additional  mopping  of  pitch.  Where  laps  are  left  to  be  connected 
after  other  work  is  completed,  they  shall  be  not  less  than  10  inches 
wide  and  at  least  two  of  the  five  plies  shall  be  of  reinforced  felt,  and 
care  shall  be  taken  to  protect  such  laps  while  other  work  is  in  progress. 

Where  waterproofing  is  applied  on  the  exterior  of  perpendicular 
walls,  it  must  be  permanently  protected  by  a  layer  of  concrete  or 
course  of  brick,  and  until  such  permanent  protection  is  in  place, 
care  must  be  taken  not  to  break  or  injure  the  waterproofing  in  any 
way.  On  horizontal  waterproofing  the  temporary  protection  must 
be  1  inch  of  cement  mortar  applied  immediately  after  the  felt  and  the 
pitch  are  laid. 

*  A  straight-run  coal-tar  pitch,  having  a  melting-point  between  140  and  150 
deg.  Fahr.  by  the  cube-in-water  method. 

t  A  tar-saturated  felt  of  good  grade  and  medium  weight. 

t  This  reinforced  felt  is  composed  of  one  layer  of  tar-saturated  felt  bonded 
to  one  layer  of  unsaturated  cotton-woven  fabric.  This  combination  is  used  as  a 
single  ply  in  itself.  .  . 


WATERPROOFING   SPECIFICATIONS  279 

t 

On  all  interior  waterproofing,  the  permanent  covering  must  be 
of  sufficient  weight  and  strength  to  withstand  the  maximum  water 
pressure. 

Specifications  for  Waterproofing  Subsurface  Structures  by  the 
Integral  Motor  Surface  Coating  Method.  Waterproofing  shall  con- 
sist of  cement  mortar  facings  waterproofed  with  C.*  These  facings 
(or  coatings)  shall  be  applied  to  those  surfaces  of  walls  (interior  or 
exterior  below  grade);  upper  surface  of  floor  slabs;  basement  and 
sub-basement;  pits,  tunnels,  etc.,  where  waterproofing  is  indicated 
in  plans  and  specifications. 

The  mortar  for  these  facings  shall  be  composed  of  one  part  of 
cement  of  brand  approved  by  architect,  two  parts  of  clean  sharp 
sand,  to  which  shall  be  added  1J  gallons  of  C  for  each  bag  of  cement. 

These  waterproof  facings  shall  be  from  f  to  1  inch  applied  in  at 
least  two  coats  on  walls  and  not  less  than  1  inch  thick  applied  in 
one  coat  on  floor  surfaces.  The  finish  coat  shall  be  well  floated  to 
close  all  pores. 

Thoroughly  mix  the  cement  and  sand  dry. 

Put  enough  C  for  one  batch  into  an  empty  barrel  and  add  a  small 
quantity  of  water,  stirring  until  entirely  smooth.  Then  stir  in  more 
water,  but  not  more  than  will  be  required  to  give  a  stiff  mortar. 

Mix  this  liquid  in  the  cement  and  sand  as  usual,  turning  over 
until  the  color  of  the  mortar  is  uniform. 

The  measured  amount  of  C  may  be  added  to  the  charge  in  a 
batch  mixer  without  first  dissolving  in  the  gaging  water;  no  more 
than  the  usual  time  of  mixing  is  needed. 

Where  the  masonry  is  new,  clean  and  rough,  it  is  necessary  merely 
to  saturate  the  surface  with  water.  It  is  very  important  to  use  as 
much  water  as  the  surface  will  take  up;  otherwise  the  mortar  will 
be  sucked  dry  before  it  has  a  chance  to  set  properly. 

Old  surfaces,  such  as  smooth  concrete,  brick- work,  stone,  etc., 
must  be  chipped,  bush-hammered  or  sand-blasted  until  suitably 
rough;  rubbed  with  a  wire  scratch-brush  to  remove  loose  particles, 
paint,  slime,  etc.;  washed  with  dilute  muriatic  acid  (mixed  one  to 
four  in  a  wooden  pail),  and  finally  flushed  down  with  clean  water  to 
remove  all  traces  of  acid.  After  seeing  that  the  wall  is  saturated 
v/ith  water,  the  mortar  must  be  applied  as  soon  as  possible. 

Over  a  very  hard,  seasoned  concrete,  a  thin  cement  wash,  applied 
before  the  mortar  coat,  and  allowed  to  harden  slightly,  will  promote 
the  adherence  of  the  new  mortar.  ,*« 

*  These  specifications  are  for  the  use  of  a  proprietary  asphaltic-emulsion 
paste  compound,  herein  designated  by  C. 


280  WATERPROOFING  ENGINEERING 

C  waterproofing  compound  will  not  make  up  for  careless  or  un- 
skilled labor.  The  precautions  of  ordinary  good  practice  must  be 
observed  in  every  point,  just  as  if  C  were  not  used. 

Remarks.  The  company  issuing  the  above  specifications  is 
frank  enough  to  admit  that  the  material  it  specifies  will  not  make 
up  for  careless  or  unskilled  labor,  and  that  the  precautions  of  good 
practice  must  be  observed  in  every  point  if  the  waterproofing  mate- 
rial is  to  be  effective.  In  Chapters  II  and  X  will  be  found  facts 
and  figures  showing  what  may  be  accomplished  by  the  use  of  experi- 
enced labor  and  careful  supervision  without  the  addition  of  any  in- 
tegral waterproofing,  if  the  importance  of  the  work  warrants  the 
expense  of  these  extra  precautions. 

SPECIFICATIONS  FOR  WATERPROOFING  TUNNELS  AND  SUBWAYS 

Specifications  for  Waterproofing  New  York  Subways  *  by  the 
Membrane  and  Brick-in-mastic  Systems.  General  Directions.  In 
general,  waterproofing  of  the  structure  will  be  limited  to  the  roof 
and  to  those  surfaces  near  ground  water  or  mean  high  water  if  ground- 
water  level  is  found  for  any  reason  to  be  below  mean  high  water. 
At  other  places  free  drainage  shall  be  provided  by  pipe  drains,  hollow 
tile  or  broken  stone. 

At  the  stations  the  entire  structure  shall  be  waterproofed. 

The  protecting  masonry  shall  be  concrete,  common  bricks  or 
hollow  terra-cotta  blocks  as  directed,  and  shall  be  not  less  than  four 
(4)  inches  in  thickness. 

In  places  where  permanent  sheeting  is  placed  at  the  waterproofing 
line,  the  waterproofing,  if  permitted  by  the  engineer,  may  be  applied 
against  the  sheeting. 

All  surfaces  to  which  waterproofing  is  to  be  applied  shall  be  made 
as  smooth  as  possible;  on  these  surfaces  there  shall  be  spread  hot 
melted  coal-tar  pitch  in  a  uniformly  thick  layer;  on  this  layer  of 
pitch  shall  be  laid  a  treated  woven  fabric  of  such  material  as  may  be 
approved  by  the  engineer;  this  process  shall  be  repeated  until  such 
number  of  layers  as  may  be  required  by  the  engineer  have  been  placed 
and  a  final  coat  of  the  pitch  shall  then  be  applied. 

The  term  "  ply  "  as  used  in  these  specifications  shall  mean  a  layer 
of  treated  woven  fabric  (except  the  dry-ply),  both  sides  of  which 
shall  be  coated  with  coal-tar  pitch  at  the  time  of  laying. 

The  number  of  plies  of  waterproofing  over  the  roof  between  sta- 

*  Dual  Subway  System  built  under  supervision  of  Public  Service  Commission 
for  the  First  District,  State  of  New  York,  D.  L.  Turner,  Chief  Engineer. 


WATERPROOFING  SPECIFICATIONS  281 

tions  shall  in  no  case  be  less  than  three  (3),  except  as  hereinafter 
provided  where  brick  laid  in  asphalt  mastic  is  used. 

On  the  sidewalls  at  the  station  the  same  conditions  as  in  the  pre- 
ceding paragraph  shall  apply. 

On  the  sides  and  bottom  of  the  structure  below  a  line  two  (2) 
feet  above  ground  water,  or,  if  ground  water  is  below  mean  high- 
water  level,  then  (2)  feet  above  mean  high  water,  one  (1)  ply  of  water- 
proofing, as  described  above,  shall  be  used  with  one  or  more  courses 
of  brick  laid  in  asphalt  mastic;  the  number  of  courses  of  brick  to 
be  determined  by  the  engineer. 

The  requirements  in  the  preceding  paragraphs  of  this  section 
likewise  shall  apply  to  the  roof  of  the  structure  within  station  limits 
and  over  the  tracks  passing  through  the  station  within  said  limits. 

The  quality  of  brick  used  for  brick-in-mastic  waterproofing 
shall  be  the  best  quality  common  brick,  burned  hard  entirely  through, 
regular  and  uniform  in  shape.  The  brick  shall  be  properly  dried 
and  shall  be  heated  before  laying. 

Six  (6)  plies  of  waterproofing  fabric  may  be  substituted  for  brick- 
in-asphalt-mastic,  if  approved  by  the  engineer,  and  will  be  paid  for  as 
provided  for  fabric  waterproofing. 

Asphalt  mastic  shall  contain  not  less  than  one-third  (i)  asphalt, 
the  other  ingredients  to  be  sand  and  limestone  dust  or  sand  and 
cement.  The  ingredients  are  to  be  in  proportions  governed  by  local 
requirements  and  weather  conditions.  In  melting  and  mixing  the 
mastic  its  temperature  shall  not  exceed  350  deg.  Fahr.  (177  deg. 
Cent.) 

Any  masonry  that  is  found  to  leak  at  any  time  prior  to  the  com- 
pletion of  the  work  and  final  acceptance  thereof  shall  be  cut  out  and 
the  leak  stopped,  at  the  sole  expense  of  the  contractor. 

Both  the  coal-tar  pitch  and  the  asphalt  must  be  delivered  on  the 
work  in  packages  that  are  plainly  marked  with  the  manufacturer's 
brand,  and  indicating  the  grade  and  quality  of  the  material. 

The  coal-tar  pitch  shall  be  straight-run  pitch  containing  not 
less  than  twenty-five  (25)  per  cent  and  not  more  than  thirty-two 
(32)  per  cent  of  free  carbon,  which  will  soften  at  approximately  70 
deg.  Fahr.  (21  deg.  Cent.),  and  melt  at  120  deg.  Fahr.  (49  deg. 
Cent.)  (by  the  cube-in-water  method)  being  a  grade  in  which  dis- 
tillate oils  distilled  therefrom  shall  have  a  specific  gravity  of  1.05. 

The  asphalt  used  shall  consist  of  fluxed  natural  asphalt,  or 
asphalt  prepared  by  the  careful  distillation  of  asphaltic  petroleum, 
subject  to  the  approval  of  the  engineer,  but  however  prepared,  it 
shall  comply  with  the  following  requirements: 


282  WATERPROOFING  ENGINEERING 

The  asphalt  shall  contain  in  its  refined  state  not  less  than  ninety- 
five  (95)  per  cent  of  bitumen  soluble  in  cold  carbon  disulphide, 
and  at  least  ninety-eight  and  one-half  (98J)  per  cent  of  the  bitumen 
soluble  in  cold  carbon  disulphide  shall  be  soluble  in  cold  carbon 
tetrachloride.  The  remaining  ingredients  shall  be  such  as  not  to 
exert  an  injurious  effect  on  the  work. 

The  asphalt  shall  not  flash  below  350  deg.  Fahr.  (177  deg.  Cent.) 
when  tested  in  the  New  York  State  Closed  Oil  Tester.  When  twenty 
(20)  grams  of  the  material  are  heated  for  five  (5)  hours  at  a  tempera- 
ture of  325  Fahr.  (163  deg.  Cent.)  in  a  tin  box  two  and  one-half 
(2|)  inches  in  diameter,  it  shall  not  lose  over  three  (3)  per  cent  by 
weight,  nor  shall  the  penetration  at  77  deg.  Fahr.  (25  deg.  Cent.) 
after  such  heating  be  less  than  one-half  (J)  of  the  original  penetra- 
tion. 

The  consistency  shall  be  determined  by  the  penetration  which 
must  be  between  75  and  100  at  77  deg.  Fahr. 

The  melting-point  of  the  material  shall  be  between  115  and  135 
deg.  Fahr.  (46  and  57  deg.  Cent.)  as  determined  by  the  Kraemer 
and  Sarnow  method. 

Penetrations  indicated  herein  refer  to  the  depth  of  penetration 
at  77  deg.  Fahr.  in  hundredth  centimeters  of  a  No.  2  cambric  needle 
weighted  to  one  hundred  (100)  grams  acting  for  five  (5)  seconds. 

A  briquette  of  the  solid  bitumen  of  cross-section  of  1  sq.  cm. 
shall  have  a  ductility  of  not  less  than  twenty  (20)  cm.  at  77  deg. 
Fahr.  the  material  being  elongated  at  the  rate  of  five  (5)  cm.  per 
minute.  (Dow  molds.) 

All  tests  herein  specified  must  be  conducted  according  to  methods 
approved  by  the  engineer. 

The  fabric  to  be  used  shall  be  a  woven  fabric  which  shall  have 
been  treated  with  coal-tar  pitch  or  asphalt  before  being  brought  on 
the  work.  The  fabric  *  and  the  material  used  in  its  treatment  shall 
be  approved  by  the  engineer. 

All  concrete  shall  be  dry  before  waterproofing  is  attached.  If, 
in  the  judgment  of  the  engineer,  it  is  impracticable  to  have  the  con- 
crete dry,  then  there  shall  be  first  laid  a  layer  of  treated  felt  of 
approved  quality,  on  the  upper  surface  of  which  is  to  be  spread  the 
first  layer  of  pitch  or  asphalt. 

Each  layer  of  pitch  or  asphalt  must  completely  and  entirely 
cover  the  surface  on  which  it  is  spread  without  cracks  or  blow 
holes. 

The  fabric  must  be  rolled  out  into  the  pitch  or  asphalt  while  the 
*  For  fabric  specifications,  see  p.  205, 


WATERPROOFING  SPECIFICATIONS  283 

latter  is  still  hot,  and  pressed  against  it  so  as  to  insure  its  being 
completely  stuck  over  its  entire  surface,  great  care  being  taken  that 
all  joints  are  well  broken  by  overlapping,  and  that,  unless  other- 
wise permitted,  the  ends  of  the  rolls  of  the  bottom  layers  are  carried 
up  on  the  inside  of  the  layers  on  the  sides,  and  those  of  the  roof 
down  on  the  outside  of  the  layers  on  the  side  so  as  to  secure  a  full 
lap  of  at  least  one  (1)  foot.  Especial  care  must  be  taken  with  this 
detail. 

When  the  finishing  layer  of  concrete  is  laid  over  or  next  to  the 
waterproofing  material,  care  must  be  taken  not  to  break,  tear  or 
injure  in  any  way  the  outer  surface  of  the  pitch  or  asphalt. 

None  but  competent  men,  especially  skilled  in  work  of  this  kind, 
shall  be  employed  to  lay  the  waterproofing. 

Standard  Specifications  fcr  Waterproofing  the  Philadelphia 
Subways  by  the  Sheet-mastic  Brick-in-mastic  and  Membrane 
Systems.  It  is  the  intent  of  these  Specifications  *  to  secure  a  sub- 
way structure  that  shall  be  entirely  free  from  percolation  of  outside 
water,  and  the  contractor  shall  do  all  the  work  in  such  manner  and 
take  such  precautions  as  will  secure  this  result  and  shall  guarantee 
the  watertightness  of  the  work  for  three  (3)  years.  Surfaces  shall 
be  hard  and  dry  before  any  waterproofing  is  attached,  and  shall 
first  be  coated  with  an  asphalt  paint  made  from  the  asphalt  herein 
specified  diluted  with  42  deg.  Baume  naphtha  to  the  proper  con- 
sistency and  free  of  oil.  If  for  any  reason  it  is  impracticable  to 
have  the  surface  dry,  and  the  engineer  so  orders,  there  shall  first  be 
applied  one  (1)  layer  of  double-thick  roofing  felt. 

The  waterproofing  shall  be  done  as  follows: 

The  roof  shall  be  waterproofed  with  two  (2)  layers  of  asphalt 
mastic,  each  one-half  (|)  inch  thick,  and  protected  on  top  by  three 
(3)  inches  of  1  :  3  :  6  concrete. 

The  floor  or  invert  shall  be  waterproofed  with  one  (1)  ply  of 
treated  fabric  in  compound  and  two  (2)  courses  of  hard  brick,  laid 
flat  in  compound,  all  laid  on  a  bottom  course  of  1  :  2  :  4  concrete. 

The  side  walls  shall  be  waterproofed  with  one  (1)  ply  of  fabric 
treated  in  compound,  against  four  (4)  inches  of  1  :  3  :  6  concrete, 
four  (4)  inches  of  hollow  tile  brick  or  the  concrete  sheathing  of  the 
trenches.  Against  the  fabric  shall  be  laid  eight  and  one-half  (8£) 
inches  of  brick  dipped  in  compound.  The  sidewall  treatment  shall 
extend  up  to  an  elevation  two  (2)  feet  above  ground  water  line. 

^The  asphaltic  compound  to  be  used  for  waterproofing  or  for  the 

*  Standard  Specifications  for  Construction  of  Subway  Structure;  Dept.  of 
City  Transit,  City  of  Philadelphia,  January,  1917. 


284  WATERPROOFING  ENGINEERING 

preparation  of  mastic  shall  be  composed  of  fluxed  refined  natural 
lake  asphalt,  or  of  asphalt  obtained  by  the  distillation  of  asphaltic 
petroleum.  It  shall  contain  at  least  ninety-five  (95)  per  cent  of 
bitumen  soluble  in  carbon  disulphide  (€82),  shall  have  a  melting- 
point  between  150  and  180  deg.  Fahr.  by  the  cube  method,  and  a 
ductility  at  40  deg.  Fahr.  of  at  least  5  cm.,  and  at  77  deg.  Fahr.  of 
at  least  20  cm.  by  the  Dow  method.  The  mastic  shall  be  prepared 
on  the  work  by  thoroughly  mixing  with  the  asphaltic  compound 
properly  graded  limestone  dust  and  sand,  at  a  temperature  between 
300  and  375  deg.  Fahr.,  so  as  to  make  a  homogeneous  mass.  The 
mastic  shall  be  proportioned  as  follows: 

Soluble  bitumen,  12  to  18  per  cent  as  may  be  found  necessary; 
Mineral  aggregate  passing  200-mesh  screen,  25  to  30  per  cent; 
Mineral  aggregate  passing  50-mesh  screen,  20  to  30  per  cent; 
Mineral  aggregate  passing  4-mesh  and  retained  on  10-mesh  screen, 
20  to  30  per  cent. 

Coal-tar  pitch,  if  used  for  either  fabric  waterproofing  or  for  the 
"  brick  in  compound  "  method,  shall  be  straight-run  residue  from  the 
distillation  of  coal  tar.  It  shall  have  at  least  seventy-five  (75)  per 
cent  of  bitumen  soluble  in  benzol  (CeHe),  a  melting-point  between 
120  and  140  deg.  Fahr.,  and  a  ductility  at  40  deg.  Fahr.  of  at  least 
5  cm.  Where  coal-tar  pitch  is  to  be  used  for  waterproofing,  the 
sizing  paint  to  be  applied  to  the  concrete  surfaces  in  advance  of  the 
waterproofing  shall  be  raw  coal-tar. 

The  plans  show  the  invert  and  sidewalls  of  the  subway  structure 
waterproofed,  where  waterproofing  is  expected  to  be  necessary, 
by  brick  laid  in  compound,  but  all  or  part  of  this  work  may  be 
ordered  to  be  done  by  using  one  or  more  plies  of  the  fabric  water- 
proofing. 

The  brick  used  in  waterproofing  shall  be  straight  and  hard,  of  the 
quality  prescribed  for  "  Brick  Masonry."  The  floor  and  sidewalls 
of  the  subway  structure  shall  be  waterproofed  in  the  following  man- 
ner :  The  excavation  for  the  subway  floor  shall  be  made  to  the  proper 
grade  and  thereon  shall  be  placed  a  layer  of  1  :  2  :  4  concrete,  trow- 
eled smooth  on  top.  After  this  concrete  has  set  and  is  hard  there 
shall  be  spread  on  it  a  complete  layer  of  the  hot  compound  described 
above,  as  thick  as  is  workable,  without  cracks  or  blow  holes.  On^ 
(1)  layer  of  the  treated  fabric  shall  be  spread  on  the  coated  surface 
while  the  compound  is  still  hot  and  be  pressed  flat  against  its  entire 
surface  with  an  electrically  heated  iron,  so  that  it  shall  firmly  adhere 
to  the  surface  without  bubbles  or  air  spaces.  The  exposed  surface 


WATERPROOFING  SPECIFICATIONS  285 

of  the  fabric  shall  then  be  completely  coated  with  hot  compound. 
On  this  surface  two  (2)  courses  of  brick  shall  be  laid  flat.  The 
brick  shall  have  previously  been  dried,  and  while  warm  shall  be 
dipped  in  compound  and  laid  on  a  bed  of  the  compound  on  the 
coated  fabric.  The  compound  shall  completely  fill  the  spaces  between 
the  bricks  and  the  top  course  finished  off  with  a  thin  layer  of  the 
compound.  The  waterproofing  shall  be  continuous  and  extend 
around  all  projections  of  the  invert  and  sidewalls  of  the  subway. 
Upon  the  coated  brick  laid  on  the  invert  there  shall  be  built  at  the 
sides  the  waterproofing  for  the  sidewalls  by  placing  one  (1)  ply 
of  treated  fabric  as  herein  described  against  the  concrete  sheeting, 
or  against  four  (4)  inches  1:3:6  concrete  or  hollow-tile  masonry. 
Against  this  coated  layer  of  fabric  there  shall  be  laid  eight  and 
one-half  (8J)  inches  of  dried  warm  brick,  dipped  in  hot  compound 
and  laid  in  compound  while  hot.  The  bricks  shall  break  joint, 
and  the  spaces  between  the  bricks  be  completely  filled  with  com- 
pound. 

The  fabric  shall  be  an  approved  woven  cotton  cloth,  weighing 
before  treatment,  not  less  than  5  ounces  per  square  yard-,  with  at 
least  thirty  (30)  threads  per  inch.  It  shall  be  thoroughly  saturated 
with  the  asphaltic  compound  described  above  before  laying,  shall 
have  no  admixture  or  coating  of  mineral  or  other  matter,  and  shall 
weigh  after  saturation  not  less  than  fourteen  (14)  ounces  per  square 
yard.  The  term  "  ply  "  shall  be  understood  to  mean  a  layer  of  woven 
cotton  fabric  saturated  with  compound  before  laying,  with  a  layer 
of  compound  on  each  side  of  it  applied  in  laying.  A  complete  layer 
of  hot  compound  as  thick  as  is  workable  shall  be  evenly  spread  on 
the  surface  to  be  waterproofed,  without  cracks  or  blow  holes.  The 
fabric  shall  then  be  spread  on  the  coated  surface  while  the  compound 
is  still  hot,  and  be  pressed  flat  against  its  entire  surface  with  an 
electrically  heated  iron,  so  that  it  shall  firmly  adhere  to  the  surface 
without  bubbles  or  air  spaces.  The  exposed  surface  of  the  fabric 
shall  then  be  completely  coated  with  the  hot  compound.  Where 
steel  or  concrete  sheathing  is  placed  at  the  waterproofing  line,  the 
waterproofing  from  the  floor  line  to  two  (2)  feet  above  ground  water 
line  shall  be  applied  against  the  sheathing. 

Asphaltic  material  shall  be  delivered  to  the  work  in  original  pack- 
ages, marked  with  the  manufacturer's  name  and  brand,  and  indicating 
the  grade  and  quality  of  the  material. 

Where  holes  or  void  spaces  are  to  be  filled  or  built  in  after  the 
removal  of  temporary  posts,  shores  or  braces,  the  utmost  care  shall 
be  taken  to  bond  the  new  concrete  or  other  material  to  the  prior 


286  WATERPROOFING  ENGINEERING 

work,  and  to  make  the  placing  of  patches  of  waterproofing  continu- 
ous and  watertight.  The  contractor  shall  execute  his  work  in  such 
a  manner  as  to  eliminate  as  far  as  possible  such  patchwork. 

Every  care  shall  be  exercised  not  to  puncture  or  otherwise  injure 
the  waterproofing  after  it  is  in  place  and  when  applying  the  protect- 
ing masonry.  If  any  leaks  are  found  before  the  completion  of  the 
work,  the  defective  portions  shall  be  cut  out  and  efficiently 
repaired. 

Only  competent  men  skilled  in  this  particular  class  of  work  will 
be  'permitted  to  do  the  waterproofing.  The  contractor  will  be 
required  to  guarantee  the  efficiency  of  waterproofing  by  the  render- 
ing of  watertight  structure  during  the  three-year  period  for'  main- 
tenance. 

Waterproofing  shall  not  be  done  when  exposed  to  wet  weather, 
nor  to  a  temperature  below  40  deg.  Fahr.,  and  it  shall  be  applied 
only  when  the  surface  to  be  treated  is  perfectly  dry. 

Remarks.  The  above  specifications  refer  to  the  method  of  deter- 
mining the  melting-point  of  bitumen  as  the  "cube-method"; 
there  are  two  distinct  methods  for  finding  the  melting  point  of  bitu- 
mens that  fall  under  this  head;  one  is  the  "  cube-in-air,"  the  other 
is  the  "  cube-in- water  "  method,  the  latter  giving  lower  results  for 
the  same  bitumen  and  is  not  as  suitable  for  asphalt.  It  would  be 
better  if  the  exact  method  preferred  were  stated  in  the  specification. 

The  specifications  further  call  for  bricks  to  be  imbedded  not  in 
the  usual  mastic  but  in  pure  asphalt.  A  good  mastic  is  stronger  than 
its  constituent  asphalt.  Mastic  is  also  more  substantial  than  pure 
asphalt  and  cheaper  as  well.  For  these  reasons  alone,  brick-in- 
mastic  is  preferable  to  brick-in-asphalt. 

The  specifications  permit  the  use  of  coal-tar  pitch  with  a  melting- 
point  between  120  and  140  deg.  Fahr.  For  waterproofing  by  the 
membrane  system,  coal-tar  pitch  of  this  melting-point  has  been  very 
successfully  used  on  underground  work.  But  mastic  made  of  coal- 
tar  pitch  with  a  melting-point  above  120  deg.  Fahr.  is  not  suitable 
for  subsurface  waterproofing  in  this  climate.  On  the  other  hand, 
if  the  pitch  is  intended  for  use  with  bricks  without  incorporating 
any  foreign  ingredients  it  will  lack  "  body  "  and  the  bricks  will  soon 
rest  one  upon  the  other. 

One  test  requirement  of  coal-tar  pitch  in  the  specification  is 
that  it  should  have  a  ductility  of  5  cm.  at  40  deg.  Fahr.  A  straight- 
run  coal-tar  pitch  of  the  melting-point  called  for,  has  practically 
no  ductility  at  this  temperature. 

The  specifications  also  call  for  a  woven  cotton  fabric  of  a  certain 


WATERPROOFING  SPECIFICATIONS  •     287 

weight,  raw  and  treated;  as  weight  has  little  bearing  on  the  strength 
of  the  material  it  would  seem  a  better  policy  to  specify  a  tensile 
strength.  A  woven  cotton  fabric  whose  ratio  of  tensile  strength  in 
the  warp  and  woof  approaches  unity,  is  best  for  the  purpose  of  water- 
proofing. The  tensile  strength  in  the  warp  should  not  be  less  than 
60  pounds  per  lineal  inch. 

Specifications  fcr  Waterproofing  Tunnels  on  the  Pennsylvania 
Railroad.*  It  is  intended  that  the  interior  of  waterproof  structures 
shall  be  permanently  free  from  moisture  or  discoloration  due  to  the 
percolation  of  water  or  other  liquids  from  outside  sources.  This 
end  shall  be  attained  by  means  of  a  continuous  flexible  waterproof 
sheet  surrounding  the  exterior  of  the  structures. 

Pitch  used  shall  be  straight-run  coal-tar  pitch,  which  shall  soften 
at  60  deg.  Fahr.  (15.5  deg.  Cent.)  and  melt  at  100  deg.  Fahr.  (36 
deg.  Cent.) :  being  a  grade  in  which  distillate  oils  distilled  therefrom 
shall  have  a  specific  gravity  of  1.05. 

The  felt  shall  be  (trade  name  and  manufacturer  giceri)  or  be  equally 
satisfactory  to  the  engineers. 

Coal-tar  pitch,  when  applied,  shall  be  at  a  temperature  of  not 
less  than  two  hundred  fifty  (250)  deg.  Fahr.  (121  deg.  Cent.).  The 
pitch  shall  be  mopped  on  the  surface  of  the  masonry  to  a  uniform 
thickness  of  not  less  than  -^  inch.  Each  layer  of  pitch  must  com- 
pletely cover  the  surface  on  which  it  is  spread  without  cracks  or 
blowholes.  The  felt  must  be  rolled  out  into  the  pitch  while  the  latter 
is  still  hot  and  pressed  against  it  so  as  to  insure  its  being  completely 
stuck  to  the  pitch  over  its  entire  surface.  Great  care  must  be  taken 
that  all  joints  in  the  felt  are  well-broken,  and  that  the  ends  of  the 
rolls  of  the  bottom  layer  are  carried  up  on  the  inside  of  the  layers 
on  the  sides,  and  those  of  the  roof  down  on  the  outside  of  the  layers 
on  the  sides,  so  as  to  secure  the  full  laps  herein  specified. 

Waterproofing  must  be  protected  against  injury  at  all  times 
to  the  satisfaction  of  the  engineers. 

Any  waterproofed  structure  that  is  found  to  leak  at  any  time  prior 
to  the  completion  of  this  contract  shall  be  made  tight  by  the  con- 
tractor in  a  manner  satisfactory  to  the  engineers. 

Waterproofing  shall  consist  of  six  (6)  layers  of  felt  and  seven  (7) 
layers  of  pitch  alternating,  each  strip  of  felt  to  lap  not  less  than  one 
(1)  foot  upon  the  previously  laid  strip  and  each  section  of  water- 
proof sheet  shall  lap  at  least  one  (1)  foot  with  the  adjoining  section. 

Waterproofing  will  be  measured  by  the  square  or  one  hundred 
(100)  superficial  feet  and  paid  for  accordingly. 

*  Transactions,  American  Society  of  Civil  Engineers,  Vol.  69,  p.  211, 


288  WATERPROOFING  ENGINEERING 

Remarks.  The  above  specification  would  have  increased  merit 
did  it  not  leave  the  acceptance  of  materials,  the  protection  of  the 
waterproofing,  etc.,  to  the  discretion  of  the  field  engineer.  The 
engineer's  judgment  is  undoubtedly  sound,  and  his  intentions 
undoubtedly  good,  but  his  experience  may  be  very  limited  in  regard 
to  waterproofing  and  too  often  he  considers  waterproofing  not  a 
very  important  item  of  the  work.  The  properties  of  waterproofing 
materials  are  not  a  matter  of  common  knowledge  as  the  properties 
of  other  construction  materials  are,  neither  are  systems  of  water- 
proofing as  standardized  as  other  branches  of  construction.  It  seems 
therefore  that  the  specification  writer  would  be  amply  justified  in 
receiving  the  best  advice  and  information  regarding  these  matters 
and  incorporating  them  in  the  specification  as  a  help  and  guidance 
to  the  field  engineer.  The  melting-point  of  the  pitch  called  for 
in  the  specifications  is  indefinite  since  the  method  of  determining 
same  is  not  given. 

Specifications  for  Mixing  and  Placing  Grout  for  Waterproofing 
Tunnels.*  Under  this  item  shall  be  included  the  transportation  of 
grouting  materials,  the  operation  of  grouting  plant  and  all  other 
labor,  not  specifically  included  in  other  items,  connected  with  the 
mixing  and  placing  of  all  grout  in  any  part  of  the  work  included  in 
this  contract,  whether  such  placing  is  by  pouring,  by  forcing  through 
pipes  or  by  impregnation  by  use  of  the  grouting  pad,  under  any 
required  pressure  not  exceeding  300  pounds  per  square  inch.  The 
work  to  be  done  under  this  item  shall  include  all  requisite  precau- 
tions to  prevent  the  setting  of  grout  which  may  escape  upon  the 
exposed  surfaces  of  the  masonry,  and  all  measures  necessary  for  the 
removal  of  grout  which  may  have  adhered  to  such  surfaces  and  for 
restoring  such  surfaces  to  their  original  condition. 

Grouting  will  be  done  to  fill  all  voids  in  dry  packing  or  elsewhere 
over  the  tunnel  arch,  to  close  cracks,  seams  and  fissures  in  the 
rock  about  the  tunnel  or  shafts,  to  increase  the  imperviousness  of  the 
masonry  lining,  to  insure  a  watertight  contact  with,  and  the  com- 
plete protection  of,  steel  work  embedded  in  the  masonry,  and  for 
other  purposes  as  required. 

Except  where  it  may  be  ordered  to  reduce  leakage  in  wet  ground, 
or  to  increase  the  stability  of  shattered,  moving  or  unstable  ground, 
or  in  connection  with  sections  of  masonry  lining  built  to  control  such 
leakage  or  to  support  such  heavy  ground,  grouting  under  pressure 

*  The  above  specifications  are  extracted  from  the  general  specifications 
issued  by  the  Board  of  Water  Supply  of  the  City  of  New  York  in  1910,  for  the 
construction  of  a  portion  of  the  City  Tunnel  of  the  Catskill  Aqueduct,  in  the 
Boroughs  of  Bronx  and  Manhattan. 


WATERPROOFING  SPECIFICATIONS  289 

will  not  generally  be  ordered  under  this  item,  in  any  place,  except 
in  less  deep  portions  of  shafts  where  the  external  water-pressure  is 
comparatively  light,  until  three  months  after  placing  the  complete 
ring  of  lining  masonry  at  that  place.  Grouting  shall  be  kept  as 
nearly  up  with  the  concreting  as  the  three  months'  interval  permits. 

Grout  shall  be  mixed  of  a  consistence  suitable  to  the  work  in  hand, 
in  general  as  thick  as  can  with  certainty  be  made  to  completely  fill 
the  voids.  It  is  the  intention  to  make  grout  which  is  to  be  forced 
into  pipes  not  less  rich  than  1|  parts,  by  weight,  of  sand  or  stone 
dust  to  one  part  of  cement.  All  ingredients  shall  be  entirely  free 
from  lumps  when  put  into  the  mixer.  When  the  grouting  of  any 
seam,  void,  or  section  of  dry  packing  has  begun,  it  shall,  unless  other- 
wise expressly  ordered,  be  prosecuted  continuously  until  completed, 
without  any  intermission  long  enough  to  allow  the  grout  to  take  an 
initial  set.  In  order  to  insure  a  complete  filling  of  voids,  as  in  dry 
packing  over  the  tunnel  arch,  and  to  avoid  occluding  air  in  the 
interstices  of  such  dry  packing,  the  grout  shall  be  delivered  uni- 
formly and  steadily,  not  in  violent  spurts  or  blasts. 

By  a  sufficient  number  and  suitable  spacing  of  grout  pipes,  by 
the  simultaneous  use  of  a  sufficient  number  of  grouting  machines, 
and  by  changing  of  connections  as  required,  grouting  of  dry-packed 
spaces  or  of  other  spaces  over  the  tunnel  arch  shall  be  so  done,  except 
in  cases  where  the  engineer  deems  it  impracticable,  that  all  voids 
can  be  filled  without  requiring  any  grout  to  travel  more  than  25  feet 
after  leaving  the  grout  pipe;  and  this  distance  shall  be  reduced  as 
required.  Grouting  of  any  section  of  tunnel  shall  begin  at  the  bot- 
tom and  proceed  uniformly,  upward  unless  some  other  order  of  grout- 
ing is  directed.  In  grouting  spaces  over  the  tunnel  arch  through 
pipes  having  their  upper  ends  at  different  elevations,  grouting  shall 
invariably  begin  at  the  lowest  pipes,  and  no  connection  shall  be  made 
to  pipes  higher  up  until  the  grout  has  completely  filled  the  space 
below  such  higher  pipes,  as  shown  by  the  grout  flowing  out  of  them. 
These  spaces,  whether  dry-packed  or  not,  are  to  be  divided  into 
sections  of  a  length  not  exceeding  50  feet  by  masonry  cut-off  walls 
built  across  them  and  tight  against  the  tunnel  roof. 

Wherever  50-foot  sections  over  the  tunnel  arch,  or  other  large 
voids,  are  being  grouted,  such  number  of  grouting  machines  as  may 
be  ordered,  generally  not  less  than  two,  shall  be  concentrated  on 
each  such  section  or  void.  Grouting  will  be  considered  to  be  com- 
pleted, in  each  case,  when  no  more  grout  can  be  forced  into  the  seam, 
void  or  dry-packed  space  under  the  required  pressure  up  to  300  pounds 
per  square  inch. 


290  WATERPROOFING  ENGINEERING! 

Regrouting  of  sections  of  shaft  or  tunnel  once  grouted  shall  be 
done  if  and  as  required.  Water  may  be  ordered  forced  into  pipes 
for  the  purpose  of  opening  channels  in  grout  previously  placed,  or 
for  other  purposes,  in  which  case  any  required  pressure  up  to  300 
pounds  per  square  inch  shall  be  applied. 

Under  the  item  of  sand  for  grout  the  contractor  shall  furnish  at 
some  central  point  natural  or  artificial  sand  of  the  quality  below 
specified,  for  grout.  The  specifications  for  sand  for  concrete  shall 
apply  equally  to  the  sand  furnished  hereunder,  except  that  the  sand 
for  grout  is  to  be  of  such  fineness  that  100  per  cent  will  pass  a  sieve 
having  sixty-four  openings  per  square  inch,  and  45  per  cent  will 
pass  a  sieve  having  1600  openings  per  square  inch,  the  wires  of  the 
sieves  being  respectively,  0.035  and  0.013  inch  in  diameter.  To 
obtain  this  degree  of  fineness  it  may  be  necessary  to  roll  coarser 
natural  sand  or  stone  screenings. 

For  convenience  in  handling  and  measuring  into  the  grouting 
machine  the  sand  shall,  unless  otherwise  specifilly  permitted,  be  put 
up  in  strong  sacks  each  containing  a  standard  weight  of  sand  con- 
taining not  more  than  an  ordinary  degree  of  moisture  (3  to  5  per  cent) . 
The  quantity  to  be  paid  for  under  this  item  shall  be  the  number  of 
toni  of  sand  actually  mixed  in  grouting  machines,  in  accordance 
with  order,  for  grout  placed  as  above  specified. 

The  quantity  to  be  estimated  for  payment  under  this  term  shall 
be  the  number  of  cubic  yards  of  liquid  grout  actually  mixed  in  accord- 
ance with  orders.  The  volume  will  be  computed  from  the  quantities 
of  dry  materials,  on  the  assumption  that  the  grout  is  mixed,  in  each 
case,  of  the  consistency  established  as  a  standard  for  that  case.  The 
contractor  shall  keep  an  accurate  tally  of  the  quantities  of  materials 
used  in  grout  each  day,  in  each  heading  or  shaft,  and  shall  report 
such  quantities  to  the  engineer  not  later  than  the  following  day. 
From  time  to  time  as  the  engineer  deems  necessary,  tests  will  be 
made  to  determine  the  relation  between  the  volume  of  grout  and  the 
quantities  of  the  dry  materials,  and  the  estimates  will  be  based  upon 
these  tests. 

If  in  the  opinion  of  the  engineer  there  is  avoidable  waste  of  grout 
into  the  interior  of  shaft  or  tunnel,  the  volume  of  grout  unnecessarily 
wasted,  as  estimated  by  him,  shall  be  deducted  from  the  quantity 
to  be  paid  for. 

Remarks.  The  process  of  grouting  has  been  resorted  to  in  several 
other  places  throughout  the  country  for  sinking  shafts  in  coal  mines 
and  salt  mines,  for  waterproofing  linings  in  waterworks  tunnels  and 
inverted  siphons,  for  solidifying  rock  foundations  for  dams  and  other 


WATERPROOFING  SPECIFICATIONS  291 

structures;  but  nowhere  has  this  process  been  used  so  extensively, 
so  exhaustively  studied  and  experimented  with,  and  so  successfully 
prosecuted  as  on  the  aqueduct  grouted  under  the  above  specifica- 
tions. A  complete  description  of  the  grouting  process,  the  grouting 
equipment,  a  history  of  grouting  on  various  works,  and  a  great 
deal  of  other  valuable  information  will  be  found  in  the  Proceedings 
of  the  Brooklyn  Engineers'  Club,  Vol.  XIX,  page  131,  1915,  Brooklyn, 
New  York. 

Specification  for  Waterproofing  Pneumatic  Caisson.*  The  floors 
of  shaft  caissons  (see  Fig.  Ill)  shall  be  waterproofed  with  six  (6) 
plies  of  fabric  f  and  seven  (7)  layers  of  coal-tar  pitch.  In  order  to 
avoid  fumes  from  hot  pitch  in  compressed  air,  the  fabric  shall  be 
made  up  in  normal  air  in  pieces  or  mats  of  three  plies  with  coal-tar 
pitch  binder  (melting-point  120  deg.  Fahr.  (4Q  deg.  Cent.)  by  the 
(cube-in- water  method),  each  thickness  bonding  four  (4)  inches  on 
edges.  These  triple  layers  shall  be  in  pieces  of  convenient  size  as 
required  by  the  engineer  and  shall  be  passed  through  the  airlock 
intD  the  air  chamber  of  the  caisson.  The  earth  or  rock  in  the  bot- 
tom of  the  chamber  shall  be  covered  with  a  layer  of  concrete,  about 
six  (6)  inches  in  thickness,  troweled  smooth  with  a  coating  of  mortar 
containing  equal  parts,  by  volume,  of  cement  and  sand.  Upon  this 
coating  shall  be  spread  a  layer,  not  less  than  one-sixteenth  (^) 
inch  in  thickness  of  soft  pitch  which  will  soften  at  32  deg.  Fahr. 
(0  deg.  Cent.)  and  melt  at  about  60  deg.  Fahr.  (15.5  deg.  Cent.) 
so  that  it  can  be  spread  without  heating.  Upon  this  shall  be  spread 
a  triple  layer  of  fabric  with  lap  of  twelve  (12)  inches  on  longitudinal 
joints  giving  four-ply  along  the  laps,  and  with  lap  cf  eighteen  (18) 
inches  on  transverse  joints.  All  laps  shall  be  laid  in  soft  coal-tar 
pitch.  The  three-ply  layer  shall  be  covered  with  a  layer  of  one- 
sixteenth  (r§-)  inch  of  soft  pitch,  and  another  three-ply  layer  of 
fabric,  laid  in  the  manner  described,  and  so  as  to  break  joints  with 
the  first  layer,  followed  by  a  final  coating  of  soft  pitch.  Upon  this 
shall  be  laid  one  course  of  brick,  on  the  flat,  in  mortar  containing 
equal  volumes  of  cement  and  sand.  Care  shall  be  taken  to  secure  the 
best  obtainable  bond  between  the  waterproofing  and  the  metal  work 
of  the  caissons.  Other  parts  of  the  railroad  which  are  not  lined  with 
cast  iron  and  which  are  required  to  be  waterproofed  in  compressed 
air,  may  be  required  to  be  waterproofed  in  the  manner  described 
above. 

*  Public  Service  Commission  Specifications  for  New  York  Rapid  Transit 
R.  R.  Route  48,  Section  31  (William  and  Clark  St.  Tunnel),  April,  1914. 
t  For  quality  of  fabric  here  referred  to,  see  p.  265, 


292 


WATERPROOFING  ENGINEERING 


Before  placing  the  first  course  of  concrete  in  the  floors  of  shaft 
caissons,  under  drains  shall  be  laid  to  a  central  sump  as  directed  by 
the  engineer,  and  all  tendency  to  uplift  of  the  concrete  floor  shall 


__L__^  ^___-____^_^_-_     t_^HT    g*:j.-.. 


be  prevented  by  continuous  pumping  for  a  period  of  ten  (10)  days 
after  the  completion  of  the  concrete  floor  above  the  waterproofing. 
The  arrangement  for  pumping  shall  be  such  as  to  prevent  drawing 
sand  from  beneath  the  floor.  After  the  expiration  of  said  period  of 


WATERPROOFING  SPECIFICATIONS  293 

ten  (10)  days,  pumping  from  the  sump  shall  be  suspended  and  the 
sump  capped  and  made  watertight  and  the  air  pressure  gradually 
reduced  to  one-half  the  pressure  due  to  the  hydrostatic  head.  If 
defects  in  the  waterproofing  appear,  the  contractor  shall  repair  the 
defects.  After  a  satisfactory  test,  the  concrete  filling  in  the  sump 
shall  be  completed. 

The  utmost  precautions  in  regard  to  fire  in  the  caisson  chamber 
shall  be  taken  at  all  times  while  the  waterproofing  layers  of  fabric 
and  pitch  are  exposed,  and  no  lighted  candles  or  matches  will  be 
allowed. 


SPECIFICATIONS  FOR  WATERPROOFING  RAILROAD  STRUCTURES 

Specifications  for  Waterproofing  Concrete  Structures  on  the 
Chicago,  Milwaukee  &  St.  Paul  Railway.  The  necessary  pro- 
vision- for  drainage  and  expansion  must  be  made  in  designing  the 
structure.  The  waterproofing  should  never  be  compelled  to  resist 
hydrostatic  pressure,  and  the  membrane  should  always  be  protected 
by  a  layer  of  concrete. 

Fill  all  openings  and  pockets  in  the  concrete,  except  expansion 
joints,  with  cement  mortar,  and  round  off  all  sharp  corners.  Wher- 
ever waterproofing  stops  on  a  vertical  parapet,  the  end  should  be 
flashed  into  a  groove  in  the  concrete. 

Thoroughly  clean  and  dry  the  concrete  surface,  using  wire 
brushes  and  being  careful  to  remove  all  the  laitance.  If  necessary, 
use  hot  sand  to  dry  the  concrete.  Apply  a  coat  of  gasoline  to  the 
clean  dry  surface  and  follow  with  a  coat  of  cold  primer  spreading 
the  primer  evenly  with  a  brush.  Omit  the  primer  where  tar  paper 
is  to  be  placed  and  over  expansion  joints. 

After  the  primer  coat  has  completely  dried,  apply  a  coat  of  pure 
hot  asphalt,  and  mop  until  the  layer  has  a  thickness  of  f  inch. 
While  the  asphalt  is  still  hot,  begin  laying  the  burlap.  Lay  the 
first  strip  of  burlap  transverse  to  the  drainage  at  the  lowest  point. 
Lay  the  strips  shingle  fashion,  as  for  tar  and  gravel  roofs,  and  parallel 
to  the  first  strip  working  up  to  the  summit  and  exposing  one-third 
of  each  width  of  burlap  to  the  weather.  Press  each  strip  firmly 
into  the  asphalt,  then  mop  well  with  pure  melted  asphalt  taking 
care  to  thoroughly  saturate  the  burlap  and  to  fill  all  cracks  and  blow 
holes.  Lap  the  joints  in  the  strips  6  inches.  On  this  three-ply 
layer  of  burlap  spread  a  continuous  layer  of  hot  asphalt  mopping 
well  until  a  layer  of  J  inch  is  obtained.  See  (/)  Fig.  112. 


294 


WATERPROOFING  ENGINEERING 


After  the  |-inch  layer  of  asphalt  on  top  of  the  burlap  has  become 
cold  spread  a  f-inch  layer  of  concrete  evenly  over  the  surface. 
Then  press  a  layer  of  expanded  metal  into  the  concrete  and  cover  the 
metal  with  a  layer  of  concrete  |  inch  thick  making  the  total  thick- 
ness of  the  concrete  If  inch  thick  and  trowel  the  concrete  smooth. 


Broken 
Stone 
Filling' 


(B)  SECTION  OF  EXPANSION  JOINT 
AT   OFFSET  IN  WATERPROOFING  SURFACE 


(A)  ENLARGED  SECTION  AT   BRIDGE  ABUTMENT 
Concrete^     Expanded  Metal  — •>  3  Layers  of  Burlap 


(0_)  SECTION  OF  FIXED  JOINT 
AT   OFFSET  IN  WATEBPROOFING  SURFACE 


irface  of  Waterproofing  to  conform 


to  Surf  ace  or  Base — 


Coat  of  Primer  Asphalt  • 

CD)  TRANSVERSE  SECTION  OF  WATERPROOFING 
Expanded  Metal 


(E)  TRANSVERSE  SECTION  OF  SLAB 


(F)  LONGITUDINAL  SECTION  OF  WATERPROOFING 
3  Layers  of  Burlap-. 


(GJ  DETAIL  OF  SUMMIT 


2  Layers  ofjlar  Paper )  _ 


A 

(H)  SECTION  OF  EXPANSION  JOINT 

FIG.  112.— Standard  Methods  of  Waterproofing  Bridge  Floors,  C.  M.  &  St.  P.  Ry. 

Protect  the  concrete  from  the  sun  for  twenty-four  hours  after  laying. 
The  joints  in  the  expanded  metal  should  be  lapped  6  inches.  (See 
(d)  Fig.  112). 

After  the  work  has  been  brought  up  to  the  desired  point  from  both 
sides,  interlap,  in  order,  the  strips  which  reach  across  the  joint, 
mopping  asphalt  between  burlap  surfaces.  Place  a  strip  of  burlap 


WATERPROOFING  SPECIFICATIONS  295 

along  the  joint  for  a  closing  strip;    complete  by  laying  the  upper 
|  inch  of  asphalt  as  before  described.     See  (g)  Fig.  112. 

If  possible  the  waterproofing  should  be  laid  in  one  run  the  full 
width  transverse  to  the  drain  slope  of  the  surface  to  be  waterproofed. 
The  ends  of  the  burlap  strip  should  be  flashed  into  recesses  in  the 
walls,  curbs  or  parapets  as  shown  &t  (e).  Where  longitudinal 
joints  are  necessary  cut  the  burlap  long  enough  to  extend  12  inches 
beyond  the  primed  and  asphalted  surface  of  the  concrete  and  use 
care  as  the  strips  are  laid  that  the  12-inch  strip  is  kept  free  from 
asphalt.  When  the  succeeding  section  is  to  be  waterproofed,  fold 
back  the  projecting  strips  of  burlap  over  the  completed  waterproofing 
and  bring  the  new  up  against  the  completed  portion  of  the  water- 
proofing, interlapping  the  projecting  ends  of  the  burlap  with  the  new 
burlap  as  the  work  progresses;  this  is  shown  at  (/).  On  concrete 
trestle  or  subway  slabs  longitudinal  joints  in  the  waterproofing 
should  preferably  be  on  the  center  line  of  the  slabs.  If  it  is  neces- 
sary to  place  joints  in  the  waterproofing  over  joints  in  the  slabs 
special  care  should  be  taken. 

Lay  two  continuous  strips  of  tar  paper  36  inches  wide  over  the 
expansion  joint,  being  careful  to  see  that  no  asphalt  gets  between  or 
under  the  two  strips  of  tar  paper.  Then  mop  the  top  strip  with  hot 
asphalt  and  carry  the  waterproofing  over  the  top  of  the  paper 
the  same  as  if  no  joint  existed.  See  (6)  and  (h). 

The  burlap  is  to  be  a  treated,  8-ounce,  open-mesh  burlap  fur- 
nished in  widths  of  36  to  42  inches. 

The  concrete  is  to  be  one  part  Portland  cement,  two  parts  tor- 
pedo sand  and  three  parts  stone  or  gravel  that  will  pass  a  J-inch 
ring. 

The  mortar  is  to  be  one  part  Portland  cement  and  two  parts 
washed  torpedo  sand. 

The  primer  is  made  by  pouring  hot  asphalt  in  80  deg.  Baume" 
gasoline  until  mixture  will  spread  readily  with  a  brush. 

Pure  asphalt  conforming  to  accepted  specifications  is  to  be  used. 
Before  using  the  asphalt  heat  it  in  a  suitable  kettle  to  a  temperature 
not  exceeding  450  deg.  Fahr.  (232  deg.  Cent.).  The  temperature 
is  to  be  taken  with  a  thermometer.  Asphalt  heated  above  450  deg. 
Fahr.  or  giving  off  yellow  fumes  is  to  be  discarded  as  overheated. 

The  expended  metal  is  to  be  equivalent  to  (manufacturer's  name 
stated)  "  2J-inch  No.  16  Regular  "  expanded  metal.  The  tar  paper 
will  be  furnished  in  rolls  36  inches  wide. 

Remarks.  In  describing  the  color  of  fumes  coming  from  the  sur- 
face of  overheated  asphalt  as  being  yellow,  the  author  desires  to 


296  WATERPROOFING  ENGINEERING 

correct  this  general  misconception  and  state  that  the  fumes  of  burned 
asphalt  are  bluish  black  and  the  fumes  of  coal-tar  pitch  are  yellow 
with  a  greenish  tinge. 

Specifications  for  Waterproofing  Concrete  Structures  on  the 
Chicago,  Burlington  &  Quincy  Railroad.  The  waterproofing  shall 
consist  of  a  mat  of  four  ply  of  burlap  and  one  ply  of  felt  thoroughly 
saturated  and  bonded  together  with  waterproofing  asphalt  and 
covered  with  1  inch  of  sand-and-asphalt  mastic.  No  waterproofing 
shall  be  done  when  the  temperature  is  less  than  60  deg.  Fahr. 
(15.5  deg.  Cent.). 

The  surface  of  the  concrete  shall  be  smooth,  clean  and  dry. 
Upon  this  surface  there  shall  first  be  applied,  with  brushes,  a  coat 
of  priming  paint,  which  shall  be  thin  enough  to  penetrate  the  con- 
crete and  form  an  anchorage  for  the  waterproofing. 

After  this  priming  coat  has  dried,  a  heavy  coat  of  waterproofing 
asphalt,  heated  to  a  temperature  of  400  deg.  Fahr.  (204  deg.  Cent.), 
shall  be  applied  with  mops,  the  width  of  the  burlap,  and  while 
this  is  still  hot  a  layer  of  burlap  shall  be  bedded  in  it.  The  burlap 
shall  be  laid  just  behind  the  mopping  and  swept  with  a  broom,  and 
must  be  free  from  folds  and  pockets.  The  surface  of  this  burlap 
shall  be  heavily  mopped  with  waterproofing  asphalt,  and  three 
more  ply  laid  in  the  same  manner,  making  a  four-ply  burlap  mat  all 
thoroughly  saturated  and  bonded  together.  The  top  of  the  burlap 
mat  shall  be  heavily  mopped  and  one  thickness  of  felt  saturated 
with  asphalt  laid  on  it,  the  edges  lapped  at  least  3  inches,  and  sealed 
with  asphalt.  The  top  of  this  felt  shall  also  be  mopped  with  water- 
proofing asphalt.  This  shall  then  be  covered  with  1  inch  of  asphalt 
mastic  laid  in  one  layer,  the  mastic  to  be  composed  of  one  part  of 
waterproofing  asphalt  and  four  parts  of  fine  gravel  graded  from 
J  inch  to  fine  sand,  the  top  leveled  off  with  wooden  floats  and 
mopped  with  a  heavy  coat  of  asphalt. 

At  all  the  expansion  joints  in  the  concrete  a  fold,  to  allow  for  the 
expansion  of  the  structure,  shall  be  formed  by  laying  the  burlap  and 
felt  over  a  1-inch  pipe  and  removing  the  pipe  as  the  mat  is  being 
completed. 

Where  the  work  is  stopped  before  being  completed,  at  least  3  feet 
of  burlap  at  the  end  and  half  the  width  of  the  burlap  at  the  side  shall 
be  left  exposed  to  form  a  splice.  Special  care  shall  be  taken  to  seal 
the  waterproofing  at  the  sides  and  ends  of  the  bridge.  The  burlap 
and  mastic  shall  be  carried  up  the  parapet  walls  at  the  sides  and  the 
ends  concreted  in  a  recess  in  the  walls  so  that  no  water  can  enter. 
The  burlap  shall  be  carried  down  over  the  back  walls  at  the  ends  of 


WATERPROOFING  SPECIFICATIONS  297 

the  bridge  to  cover  all  construction  joints  and  shall  run  into  a  line 
of  tile  to  facilitate  the  escape  of  the  water. 

The  burlap  shall  be  8-ounce,  open-mesh,  high-grade  burlap  satu- 
rated with  an  asphalt  meeting  the  specifications  for  waterproofing 
asphalt.  It  shall  come  in  rolls  which  shall  be  placed  on  end  for  ship- 
ment and  storage,  and  shall  not  stick  together  in  the  roll.  The  felt 
shall  be  a  good  quality  wool  felt,  saturated  and  coated  with  an 
asphalt  meeting  the  specifications  for  waterproofing  asphalt.  It 
shall  come  in  rolls,  which  shall  be  placed  on  end  for  shipment  and  stor- 
age, and  shall  not  stick  together  in  the  roll.  It  shall  not  weigh  less 
than  15  pounds  per  100  square  feet.  The  primer  shall  be  an  asphaltic 
compound  of  approved  quality  and  capable  of  adhering  firmly  to  the 
concrete. 

The  waterproofing  asphalt  shall  meet  the  following  requirements: 
(1)  The  specific  gravity  of  the  asphalt  desired  shall  be  greater  than 
0.95  at  77  deg.  Fahr.  (25  deg.  Cent.).  (2)  The  flowing-point  shall 
not  be  less  than  130  deg.  Fahr.  (54.5  deg.  Cent.)  nor  more  than 
140  deg.  Fahr.  (60  deg.  Cent.).  (3)  The  flash  point  shall  not  be 
lower  than  450  deg.  Fahr.  (232  deg.  Cent.).  (4)  The  penetration 
at  80  deg.  Fahr.  (27  deg.  Cent.)  for  a  period  of  thirty  seconds  shall 
be  at  least  15  mm.  and  must  not  exceed  20  mm.  This  penetration 
to  be  measured  with  a  Vicat  needle  weighing  300  grams,  one  end 
being  1  mm.  in  diameter  for  a  distance  of  6  cm.  (5)  When  heated 
to  a  temperature  of  325  deg.  Fahr.  (163  deg.  Cent.)  for  seven  hours 
the  loss  in  weight  shall  not  exceed  2  per  cent  and  the  penetration 
of  the  residue  at  80  deg.  Fahr.  and  for  the  period  of  thirty  seconds 
using  the  same  instrument  as  described  above  shall  not  be  reduced 
more  than  50  per  cent.  (6)  The  total  soluble  in  carbon  disulphide 
shall  not  be  less  than  99  per  cent.  (7)  The  total  soluble  in  88  deg. 
naphtha  shall  not  be  less  than  70  per  cent.  (8)  The  total  inorganic 
matter  or  ash  shall  not  exceed  1  per  cent.  (9)  Cold  test,  (a)  A 
cube  of  asphalt  1  inch  on  edge  shall  be  soft  and  malleable  at  a  tem- 
perature of  0  deg.  Fahr.  (  —  18  deg.  Cent.).  (6)  A  film  of  the  asphalt 
having  a  thickness  not  less  than  ^  inch  shall  be  so  pliable  at  0  deg. 
Fahr.  that  it  can  be  bent  in  a  radius  of  2  inches.  The  total  time 
consumed  in  the  bending  of  this  film  shall  not  exceed  three  seconds. 
(10)  The  asphalt  shall  not  be  affected  by  any  of  the. following  solu- 
tions, after  being  immersed  in  them  for  a  period  of  three  days:  (a) 
A  25  per  cent  solution  of  sulphuric  acid;  (b)  a  25  per  cent  solution 
of  hydrochloric  acid;  (c)  a  20  per  cent  solution  of  ammonia. 

Remarks.  The  above  specification  differs  from  the  previous  one 
mainly  in  that  it  specifies  a  1-inch  thickness  of  asphalt  mastic  as  a 


298  WATERPROOFING  ENGINEERING 

protective  coat  over  the  membrane.  This  is  good  •  practice  but  it 
requires  very  careful  selection  of  materials,  and  good  workmanship 
in  its  preparation  and  application  for  the  best  results.  In  describing 
the  testing  of  the  waterproofing  asphalt,  no  mention  is  made  of  the 
method  of  determining  the  flowing-point.  Besides,  from  the  tem- 
perature given,  it  is  evident  that  the  melting-point  is  meant,  and  not 
the  flowing-point,  because  the  flowing-point  is  only  a  comparative 
test.* 

Limiting  the  work  of  waterproofing  to  an  atmospheric  tempera- 
ture of  60  deg.  Fahr.  is  at  least  20  deg.  too  high  and  therefore  too 
restrictive  a  clause.  A  surface-coating  of  sand  on  top  of  the  mastic 
is  an  advisable  requirement,  as  this  tends  to  prevent  abrasion  of  the 
surface  by  the  ballast. 

Specifications  for  Waterproofing  Solid-floor  Railroad  Bridges,  f 
The  depth  of  steel  or  concrete  construction  shall  be  such  as  to  allow 
a  sufficient  distance  from  top  of  rail  to  top  of  steel  or  concrete 
floor  for  proper  waterproofing  and  protection  from  the  cutting  action 
of  the  ballast.  Under  ordinary  conditions,  a  depth  of  from  3.5  to 
4.0  feet  from  top  of  rail  to  clearance  line  below  is  sufficient. 

Provision  shall  be  made  for  grades  of  at  least  1  per  cent  on  the 
floor  of  the  bridge  to  remove  water  promptly.  Where  this  cannot 
be  done  in  the  steelwork,  cement  mortar,  with  a  minimum  thick- 
ness  of  2J  inches,  shall  be  placed  so  as  to  drain  the  water  to  the  inlets. 

Cast-iron  inlets  shall  be  set  at  proper  places  in  the  floor  and 
provided  with  movable  top  grates.  The  down-spout  from  each 
inlet  shall  be  provided  with  a  trap  and  cleanout,  which  shall  be 
accessible  from  below  the  bridge.  The  down-spout  shall  be  of 
wrought  iron,  and  connected  to  a  sewer  or  arranged  according  to  local 
conditions. 

On  top  of  the  prepared  surface  of  the  concrete  shall  be  placed 
either  of  the  following: 

1.  One  or  more  thicknesses  of  felt  or  fabric,   of   quality  and 
applied  as  specified  hereafter,  together  with  proper  protection. 

2.  Asphalt  mastic  at  least  1J  inches  in  thickness,  of  quality  and 
applied  as  specified  hereafter. 

Felt,  Burlap  or  Fabric.  When  waterproofing  material  of  this 
kind  is  to  be  used,  either  of  the  following  types  shall  be  adopted: 

1.  From  four  to  six  layers  of  felt. 

2.  One  middle  layer  of  treated  burlap,  with  four  layers  of  felt. 

3.  One  layer  of  felt,  two  layers  of  burlap,  and  two  layers  of  felt. 

*  See  Chapter  VII  on  Flow-point  Test. 

f  Proceedings,  American  Society  of  Civil  Engineers,  Vol.  40,  No.  10, 


WATERPROOFING  SPECIFICATIONS  299 

4.  One  middle  layer  of  treated  burlap,  and  two  layers  of  asbestos 
felt. 

5.  Either  one  or  two  layers  of  treated  cotton-drill  fabric. 

After  the  completion  of  the  felt  or  fabric  waterproofing,  the  entire 
surface  shall  be  covered  and  protected  by  one  of  the  following 
methods : 

1.  Straight,  hard-burned  brick  laid  flat,  with  joints  filled  either 
with   waterproofing   compound   or   cement  grout.     (Waterproofing 
compound  should   only  be   used   as   a  filler  on  flat  or   nearly   flat 
surfaces.) 

2.  A  layer  of  concrete  from  2  to  2|  inches  thick  with  wire  rein- 
forcement. 

3.  A  layer  of  about  1J  inches  of  asphalt  mastic  used  only  on  top 
of  asbestos  felt. 

On  top  of  the  protection  coat,  and  outside  the  line  of  the  ties, 
a  line  of  half-round  cast-iron  pipe,  6  inches  in  diameter,  and  per- 
forated frequently,  shall  be  placed  to  collect  the  water  and  convey 
it  to  the  inlets. 

All  openings  in  the  steelwork  shall  be  thoroughly  closed,  either 
by  calking  with  burlap  dipped  in  hot  asphalt,  or  by  the  use  of  sheet 
metal  sufficient  to  maintain  the  concrete  base  before  applying  the 
burlap  and  asphalt. 

Wherever  called  for  by  the  plans,  the  decks  of  the  bridges  shall 
be  protected  with  1:3:5  concrete,  with  f-inch  stone  or  gravel, 
mixed  as  specified  hereafter,  finished  with  a  1  :  2  mix  of  cement 
mortar,  \  inch  thick,  troweled  to  a  smooth  surface  on  top.  This  con- 
crete shall  be  allowed  to  dry  thoroughly  so  as  to  prevent  the  forma- 
tion of  steam  when  the  hot  waterproofing  materials  are  applied. 

All  vertical  or  sloping  surfaces  of  concrete  or  steel  shall  be  cleaned 
of  dust,  dirt,  loose  particles,  paint,  and  grease.  The  use  of  a  hand- 
bellows  is  recommended  for  cleaning  loose  dust  and  dirt  from  the 
surfaces.  For  cleaning  paint  and  grease  from  the  steel  and  freshen- 
ing the  surfaces  of  asphalt,  where  a  junction  of  old  and  new  is  to  be 
made,  or  where  a  pocket  of  pure  asphalt  is  used  against  the  girders 
and  the  felt  or  mastic,  gasoline  shall  be  used,  either  by  swabbing 
the  surface  with  it,  or  by  pouring  a  small  quantity  over  the  surface 
to  be  cleaned  and  setting  fire  to  it.  The  use  of  a  blow-lamp  is 
also  recommended. 

These  surfaces  shall  then  be  painted  with  two  coats  of  approved 
asphalt,  diluted  with  gasoline.  The  materials  of  the  first  coat  shall 
be  proportioned  so  as  to  give  a  brownish  tint.  The  second  coat  shall 
have  a  larger  quantity  of  asphalt. 


300  WATERPROOFING  ENGINEERING 

Both  coats  of  paint  shall  be  thoroughly  applied  and  worked  into 
the  surfaces,  so  as  to  give  a  uniform  coating  of  the  asphalt. 

Paint  shall  not  be  applied  to  damp  concrete  or  steel.  The  paint- 
ing shall  be  done  immediately  in  advance  of  the  application  of  the 
waterproofing  materials  and  before  dust  has  had  time  to  collect. 

If  the  concrete  is  damp  before  the  waterproofing  is  applied,  the 
surface  shall  be  first  covered  with  a  2-inch  layer  of  hot  sand  and 
allowed  to  stand  for  from  one  to  two  hours,  after  which  the  sand 
shall  be  swept  back,  uncovering  sufficient  surface  to  begin  work, 
and  the  operation  repeated  over  a  new  surface. 

All  concrete  shall  be  of  such  consistency  that  when  dumped  in 
place  it  shall  not  require  much  tamping,  and  shall  be  laid  with  a 
view  to  be  an  aid  to  the  watertightness  of  the  structure,  and  not 
merely  a  support  for  the  waterproofing  materials.  All  showing 
surfaces  shall  be  troweled  to  a  smooth,  hard  surface. 

In  cases  where  concrete  haunching  against  girders  is  called  for  by 
the  plans,  forms  shall  be  used,  and  the  concrete  shall  be  of  a  wet 
consistency. 

On  the  prepared  surface,  apply  the  specified  number  of  layers  of 
approved  saturated  and  coated  felt  (with  a  finished  surface)  weighing 
about  14  pounds  per  100  square  feet. 

The  bids  shall  be  based  on  the  use  of  the  type  of  felt  specified 
in  the  above  paragraph,  but  additional  alternate  bids  will  be  con- 
sidered, based  on  felts  or  fabrics  other  than  these,  which  may  be 
approved  by  the  chief  engineer.  In  the  event  of  such  alternate 
bids  being  made,  the  bidders  shall  present  with  them  sufficient  data 
as  to  the  methods  of  manufacture,  quality  of  materials,  and  references 
to  places  where  such  felts  or  fabrics  have  been  used,  giving  dates  of 
application. 

All  materials  shall  be  delivered  on  the  work  in  their  original 
packages,  and  properly  branded. 

The  asphalt  used  shall  consist  of  fluxed  natural  asphalt,  or  asphalt 
prepared  by  the  careful  distillation  of  asphaltic  petroleum. 

It  shall  contain,  in  its  refined  state,  not  less  than  98  per  cent  of 
bitumen  soluble  in  cold  carbon-disulphide.  The  remaining  ingre- 
dients shall  be  such  as  not  to  exert  an  injurious  effect  on  the 
work. 

When  20  grams  are  heated  for  five  hours  at  a  temperature  of 
325  deg.  Fahr.  (163  deg.  Cent.)  in  a  tin  box  2J  inches  in  diameter, 
it  shall  not  lose  more  than  2  per  cent  by  weight,  nor  shall  the  pene- 
tration at  77  deg.  Fahr.  (25  deg.  Cent.)  after  such  heating,  be  less 
than  one-half  of  the  original  penetration.  The  consistency  shall 


WATERPROOFING  SPECIFICATIONS  301 

be  determined  by  the  penetration,  which  must  be  between  .75  and 
1.00  cm.  at  77  deg.  Fahr. 

The  penetration  indicated  herein  refers  to  the  depth  of  penetra- 
tion, in  hundredths  of  a  centimeter,  of  a  No.  2  cambric  needle, 
weighted  to  100  grams,  at  77  deg.  Fahr.,  acting  for  five  seconds. 

The  melting-point  shall  be  between  150  deg.  and  190  deg.  Fahr. 
(66  and  88  deg.  Cent.). 

A  briquette  of  the  solid  bitumen,  having  a  cross-section  of  1 
sq.  cm.,  shall  show  ductility  at  40  deg.  Fahr.  (4  deg.  Cent.)  and  at  a 
temperature  of  77  deg.  Fahr.  shall  show  a  ductility  of  not  less  than 
20  cm.,  the  material  being  elongated  at  the  rate  of  5  cm.  per  min. 
(Dow  molds.) 

All  flashing  and  reinforcing  around  inlets  and  other  places  speci- 
fied shall  be  carefully  executed. 

Waterproofing  shall  not  be  done  in  wet  weather,  or  at  a  tempera- 
ture below  32  deg.  Fahr.,  without  special  orders  from  the  chief 
engineer.  The  felt  shall  be  laid  shingle  fashion,  the  first  two  layers 
longitudinally  and  the  last  three  transversely  to  the  center  line  of 
the  bridge,  where  five  layers  are  called  for,  and  as  specified  in  detail 
in  other  cases,  and  shall  be  carried  up  the  haunching  and  made  secure 
against  the  girder  in  a  satisfactory  manner.  The  flashing  against 
vertical  or  inclined  surfaces  shall  be  in  accordance  with  the  direc- 
tions of  the  chief  engineer,  if  not  indicated  on  the  plans.  The  first 
layer  of  felt  shall  not  be  cemented  to  the  floor  of  a  steel  bridge, 
except  around  the  drain  outlets.  On  an  arch  bridge,  the  first  layer 
shall  be  cemented  to  the  top  of  the  arch.  At  no  point  shall  there  be 
less  than  the  specified  number  of  thicknesses. 

As  the  hot  asphalt  is  spread,  the  felt  shall  be  immediately  rolled 
into  it,  rubbed  and  pressed  over  the  surface  so  as  to  eliminate  air 
bubbles  and  insure  thorough  sticking.  One  mopful  of  the  asphalt 
shall  not  be  spread  over  more  than  1  square  yard  of  surface  at  one 
mopping.  Not  less  than  2.5  to  3  gallons  of  asphalt  shall  be  used  on 
100  square  feet  of  a  single  layer  of  felt.  The  top  layer  shall  also  be 
mopped  and  the  work  done  so  that  the  layers  shall  be  one  compact 
mass. 

The  finish  of  the  waterproofing  against  the  girders  or  concrete 
shall  be  made  with  a  pocket  of  pure  elastic  asphalt  of  the  quality 
specified  above,  except  that  the  melting-point  shall  be  between  140 
and  180  deg.  Fahr.  (69  and  82  deg.  Cent.),  the  ductility  at  40  deg. 
Fahr.  shall  be  at  least  3  cm.  and  the  adhesive  qualities  shall  be 
satisfactory  to  the  chief  engineer.  The  surfaces  with  which  this 
material  comes  in  contact  shall  be  dry,  absolutely  free  from  dust  or 


302  WATERPROOFING  ENGINEERING 

grease,  and,  previous  to  its  application,  shall  be  covered  with  a 
thin  paint  made  by  dissolving  the  asphalt  in  gasoline. 

Particular  care  shall  be  taken  to  make  a  tight  joint  around  gus- 
sets, stiffeners,  and  the  ends  of  girders. 

Care  shall  be  taken  to  prevent  injury  in  any  way  to  the  waterproof- 
ing by  the  passing  of  men  or  wheelbarrows  over  it,  or  by  throwing 
any  foreign  materials  on  it. 

After  the  waterproofing  course  has  been  completed,  the  horizontal 
surfaces  shall  be  protected  by  a  course  of  straight,  hard-burned  and 
dense  brick,  laid  flat  in  a  bed  of  1  to  3  cement  mortar,  with  full 
joints.  There  shall  be  not  less  than  \  inch  of  mortar  between  the 
felt  and  the  bricks.  The  brick  shall  not  increase  in  weight  more 
than  10  per  cent  when  immersed  in  water  for  seven  hours. 

The  haunching,  and  about  18  inches  in  width  of  the  horizontal 
surface  adjacent  to  the  haunching,  shall  be  protected  by  about 
2J  inches  of  1  :  3  :  5  concrete,  reinforced  with  No.  8  or  No.  10  wire 
cloth,  electrically  welded. 

Every  care  shall  be  taken  to  insure  satisfactory  and  thoroughly 
watertight  joints  between  the  main  layer  of  waterproofing  and  the 
girders;  and  special  attention  shall  be  given  to  stiffeners,  gussets, 
etc.  The  waterproofing  shall  also  be  carried  down  over  the  back 
walls  to  below  the  elevation  of  the  bridge  seat,  or  as  directed. 

Rolls  of  felt  shall  be  stored  on  end,  and  not  laid  on  their  sides. 

Waterproofing  shall  be  done  only  by  experienced  and  expert 
waterproofers. 

Application  of  Waterproofing.  Wherever  called  for,  the  decks 
of  bridges  shall  be  waterproofed  with  natural  rock  asphalt  mastic, 
as  specified  below. 

The  concrete,  prepared  as  specified  heretofore,  shall  be  water- 
proofed with  asphalt  mastic  equal  in  quality,  as  to  ingredients  used 
and  resistance  to  water,  to  the  following  specifications: 

Sicilian  rock  asphalt  mastic 60  parts 

Clean,  sharp,  graded  grit  and  sand  to  pass  a  sieve  of  8 

meshes  per  inch 30  parts 

Asphalt  as  specified  above  for  membrane  binder 10  parts 

These  proportions  shall  be  varied  when  required  by  special  con- 
ditions on  the  work. 

The  mixture  shall  be  made  at  the  site  of  the  work,  shall  be  heated 
to  a  temperature  of  from  250  to  300  deg.  Fahr.  (121  to  149  deg.  Cent.) 
and  shall  be  stirred  until  all  the  ingredients  are  thoroughly  incor- 
porated. It  shall  then  be  spread  and  thoroughly  worked,  to  free 


WATERPROOFING  SPECIFICATIONS  303 

it  from  voids,  and  shall  be  ironed  to  a  smooth  surface  with  smoothing 
irons,  if  so  directed.  All  mastic  shall  be  applied  in  two  coats,  making 
the  required  thickness.  The  two  coats  shall  break  joints,  and  the 
mastic  shall  be  distributed  evenly.  Where  the  thickness  of  the 
concrete  plus  mastic  is  less  than  2J  inches,  the  full  thickness  shall  be 
made  up  of  asphalt  mastic. 

Pockets  of  asphalt  shall  be  placed  against  all  metal,  and  mastic 
along  girders,  around  stiffeners,  gussets,  etc.,  as  specified  above. 

Great  care  shall  be  taken  around  expansion  joints,  drain-pipes, 
and  similar  places,  where  a  separation  may  take  place. 

After  the  mastic  is  laid,  it  shall  be  mopped  with  pure  melted 
asphalt,  and  the  surface  shall  be  spread  with  a  layer  of  clean,  coarse 
sand,  to  harden  the  top. 

The  pockets  of  asphalt  placed  against  the  girders,  stiffeners  and 
gussets  shall  be  protected  by  about  2|  inches  of  1  :  3  :  5  concrete, 
reinforced  with  No.  8  or  No.  10  wire  cloth,  electrically  welded. 

The  furnishing  and  erection  of  the  steelwork  for  the  bridge  to 
be  waterproofed  will  be  executed  under  a  separate  contract,  and  the 
riveting  will  be  completed,  the  erection  finished,  and  the  steel  floor 
cleaned  up  ready  for  the  waterproofing,  before  the  work  on  this 
contract  is  begun.  In  addition  to  the  foregoing,  the  contractor 
shall  make  a  final  cleaning  of  the  steelwork  before  the  work  of  water- 
proofing is  begun. 

Specifications  for  Waterproofing  Station  and  Platform  Floors 
of  Railroad  Viaducts  by  the  Sheet-mastic  Method.  Where  an  asphalt 
floor  is  called  for  on  mezzanines  or  station  platforms,  it  shall  be  laid 
on  2-inch,  tongue  and  grooved,  yellow  pine,  the  maximum  width  of 
the  board  being  6  inches.  This  board  surface  shall  not  be  mopped 
with  asphalt,  but  shall  be  covered  with  a  layer  of  one-ply  building 
paper  or  untreated  felt.  Where  the  asphalt  floor  is  laid  on  concrete, 
the  dry-ply  shall  be  omitted,  and  a  mopping  of  asphalt  substituted. 

The  surface  mixture  shall  consist  of  the  following  proportions 
by  weight:  Eleven  and  one-half  (11J)  parts  of  asphalt,  ten  and  one- 
half  (10|)  parts  of  sand,  thirty  (30)  parts  of  grit,  forty-four  (44) 
parts  of  limestone  dust,  and  four  (4)  parts  of  Portland  cement. 

The  sand  shall  be  clean,  sharp,  and  free  from  dirt,  mica  and 
vegetable  matter.  It  shall  contain  both  coarse  and  fine  particles 
and  shall  be  graded  according  to  the  percentages  herein  specified. 
Sand  which  does  not  fulfill  the  above  requirements  in  its  natural 
condition  shall  be  screened,  washed,  or  mixed  with  other  sand  to 
produce  a  result  in  accordance  with  said  requirements.  Of  the  ten- 
and  one-half  (10J)  parts  of  sand,  100  per  cent  shall  pass  through  a 


304  WATERPROOFING  ENGINEERING 

ten-mesh  sieve;  40  per  cent  shall  pass  through  a  forty-mesh  sieve, 
10  per  cent  shall  pass  through  an  eighty-mesh  sieve. 

All  the  grit  shall  pass  through  a  four-mesh  sieve,  30  per  cent 
through  an  eight-mesh  sieve,  and  100  per  cent  shall  be  retained  on  a 
sixteen-mesh  sieve. 

All  limestone  dust  shall  be  of  such  fineness  that  it  shall  leave  a 
residue  of  not  more  than  20  per  cent  on  a  hundred-mesh  sieve,  and 
not  more  than  90  per  cent  on  a  two  hundred-mesh  sieve. 

The  fineness  of  the  Portland  cement  shall  be  such  that  it  shall 
leave,  by  weight,  a  residue  of  not  more  than  8  per  cent  on  a  hundred- 
mesh  sieve,  and  not  more  than  25  per  cent  on  a  two  hundred-mesh 
sieve;  the  wires  of  the  sieves  being  respectively  .0045  and  .0024  inch 
in  diameter. 

All  proportions  herein  mentioned  are  by  weight. 

The  asphalt  shall  conform  to  the  requirements  (given  in  the 
specifications  for  "  Waterproofing  Subways  by  the  Membrane 
System,"  page  281),  except  that  when  20  grams  of  the  material  are 
heated  for  five  hours  at  a  temperature  of  325  deg.  Fahr.  (163  deg. 
Cent.)  in  an  electric  oven,  the  loss  in  weight  shall  be  not  more  than 
1  per  cent  and  the  penetration  shall  be  between  .30  and  .50  cm. 
at  77  deg.  Fahr.  (25  deg.  Cent). 

The  asphalt  floor  mixture  shall  be  made  in  an  approved  mechani- 
cal mixer  or  by  hand  in  open  fire-heated  kettles.  When  made  by 
machine,  the  ingredients  should  be  weighed  out  and  put  into  the 
mixer  which  shall  cook  and  mix  the  mastic  until  it  is  of  uniform  con- 
sistency and  temperature.  Pre-heating  of  ingredients  is  dependent 
on  the  type  of  machine  used,  and  shall  be  resorted  to  as  directed  by 
the  engineer.  At  the  end  of  each  day's  work,  the  mixer  shall  be 
thoroughly  cleaned.  All  materials  used  in  making  mastic  should 
not  be  unduly  exposed  to  the  weather.  The  mastic  shall  be  brought 
to  the  place  of  application  in  wooden  pails  properly  covered  so  as  to 
retain  the  heat.  The  temperature  of  the  mastic  in  the  mixer  should 
not  exceed  400  deg.  Fahr.  (204  deg.  Cent.)  and  it  should  not  be  less 
than  300  deg.  Fahr.  (149  deg.  Cent.)  at  the  time  of  application. 

When  the  mastic  is  made  by  hand,  the  sand,  grit,  limestone  dust, 
cement  and  asphalt  shall  be  heated  to  approximately  325  deg.  Fahr., 
the  asphalt  being  heated  separately.  The  maximum  temperature 
of  the  sand,  grit  and  limestone  dust,  as  delivered  at  the  mixing 
kettle,  shall  not  exceed  375  deg.  Fahr.  (191  deg.  Cent.)  and  the 
maximum  temperature  of  the  asphalt  shall  not  exceed  350  deg.  Fahr. 
(177  deg.  Cent.). 

The  Portland    cement  shall  be  thoroughly  mixed  dry  with  the 


WATERPROOFING  SPECIFICATIONS  305 

sand,  grit  and  limestone  dust.  This  mixture  shall  then  be  sprinkled 
into  the  hot  and  molten  asphalt  until  a  homogeneous  mixture  is 
produced,  in  which  all  particles  are  thoroughly  coated  with  asphalt. 

The  mastic  shall  be  prepared  on  or  close  to  the  work  and  in 
amounts  not  exceeding  that  quantity  which  can  be  laid  in  one  working 
day.  The  maximum  temperature  of  any  batch  of  mastic  immediately 
after  being  mixed  shall  not  exceed  400  deg.  Fahr.  and  the  minimum 
temperature  when  delivered  on  the  pine  floor  shall  be  not  less  than 
300  deg.  Fahr. 

The  mastic,  containing  materials  which  will  become  separated 
by  subsidence  while  the  asphalt  is  in  a  melted  condition,  shall  be 
thoroughly  agitated  before  being  drawn  and  while  in  the  supply 
kettles.  Approved  methods  of  agitation  shall  be  used. 

The  contractor  shall,  at  his  own  expense,  provide  a  sufficient 
number  of  accurate,  properly  constructed  thermometers  for  deter- 
mining the  temperatures  of  the  mastic  at  all  stages  of  the  work. 

After  the  mixture  has  been  spread  and  compressed  to  a  uniform 
thickness  of  one  (1)  inch,  it  shall  be  rubbed  to  a  smooth  surface  with 
a  wooden  float.  Expansion  joints  shall  be  provided  where  neces- 
sary. 

Remarks.  The  above  specifications  are  used  by  the  Public 
Service  Commission,  1st  Dist.,  State  of  New  York,  on  all  new  elevated 
work  of  the  New  York  Dual  Subway  System.  The  clause  calling 
for  the  board  surface  not  to  be  mopped,  but  covered  with  a  layer 
of  building  paper  or  untreated  felt,  is  at  variance  with  most  similar 
specifications,  but  has  been  found  necessary  to  avoid  the  formation 
of  vapor  bubbles  on  the  finished  mastic  surface.  The  clause  per- 
mitting the  asphalt  floor  mastic  to  be  made  either  in  a  mechanical 
mixer  or  by  hand,  is  believed  to  be  a  good  departure  from  former 
limitation  to  hand  mixing. 

Specifications  for  Waterproofing  Concrete  Floors.  Thoroughly 
mix  one-half  each  of  D  *  and  tested  Portland  cement  by  weight. 
They  should  be  mixed  (dry)  until  absolutely  uniform  in  color  and 
showing  no  streaks.  Then  set  aside  until  ready  for  use. 

Lay  floor  base  and  topping  as  usual.  The  topping  should  be  at 
least  f  inch  thick  and  should  be  made  of  one  part  good  tested  Portland 
cement  and  two  parts  clean,  sharp,  coarse  sand,  free  from  loam  and 
clay.  See  that  the  topping  is  not  made  too  wet,  then  float  well. 

After  the  topping  is  laid  and  evened,  as  is  usually  done,  powder 
or  dust  the  floor  with  the  D  cement  mixture,  using  30  pounds  of 

*  These  specifications  are  for  the  use  of  a  proprietary  preparation  of  finely 
powdered  iron,  and  designated  by  D. 


306  WATERPROOFING  ENGINEERING 

mixture  (15  pounds  each  of  D  and  cement)  to  each  100  square  feet 
of  topping.  Use  a  small  flour  sieve  for  sifting  or  distributing  this 
mixture  over  the  surface.  Allow  dust  coat  to  stand  about  five 
minutes,  then  float  mixture  in  well  with  wooden  trowel  and  tjowel 
hard. 

When  fairly  set,  showing  no  signs  of  surplus  water  on  surface, 
trowel  a  second  time  until  the  topping  has  a  smooth,  hard  finish. 

After  the  floor  is  from  twenty-four  to  forty-eight  hours  old, 
cover  it  evenly  with  an  inch  layer  of  wet  pine  sawdust  or  shavings, 
sand  or  bags  and  rewet  same  twice  daily  for  four  or  five  days.  Do 
not  apply  the  sawdust,  etc.,  until  the  floor  is  thoroughly  set,  as  same 
may  adhere  to  and  ruin  the  finish  of  the  floor. 

Do  not  use  floor  for  seven  days,  or  while  it  is  curing.  Under  no 
circumstances  should  heavy  trucking  be  done  on  a  floor  less  than 
thirty  days  old.  Cover  the  floor  with  boards  to  assure  complete 
protection. 

SPECIFICATIONS  FOR  WATERPROOFING  ROOFS 

The  Shingle  (Tile)  Method.  The  intention  of  this  specification 
is  to  secure  a  watertight  roof  by  the  application  of  a  waterproofing 
felt  layer  and  an  overlying  covering  of  tiles.  The  roof,  prior  to  the 
application  of  the  roofing,  shall  have  been  constructed  in  strict 
accordance  with  the  plans.  The  roof  sheathing  should  be  well 
laid  and  tight,  all  chimneys  and  walls  above  roof  line  completed, 
and  all  vent-pipes  through  the  roof  properly  fastened. 

The  gutters  shall  be  placed  in  position,  extending  over  the  roof 
sheathing  (and  cant  strips,  if  same  are  used),  and  under  the  felt 
and  tile  at  least  8  inches.  All  valley  metal  shall  be  in  place,  and  the 
width  of  same  must  be  24  inches  with  both  edges  turned  up  J  inch 
for  the  entire  length  of  the  valley.  This  valley  metal  shall  be  laid 
over  one  layer  of  felt  running  the  entire  distance  of  the  valley.  All 
flashing  metal  used  alongside  and  in  front  of  dormers,  gables,  sky- 
lights, towers,  perpendicular  walls,  also  around  vent-pipes  and 
chimneys,  shall  be  placed  in  accordance  with  the  requirements  of 
the  tiles. 

Upon  the  properly  prepared  roof,  the  sheathing  shall  be  covered 
with  one  thickness  of  asphalt  or  pitch-treated  roofing  felt,  weighing 
not  less  than  30  pounds  per  square.  The  felt  should  be  laid  with 
2J-inch  laps,  and  fastened  with  capped  nails.  The  felt  shall  be 
laid  parallel  with  the  eaves,  and  lapped  about  4  inches  over  all 
valley  metal.  It  shall  also  be  laid  under  all  flashing  metal,  and  turned 


WATERPROOFING  SPECIFICATIONS  307 

up  about  6  inches  against  all  vertical  walls.  Upon  this  felt  layer 
the  tiles  shall  be  fastened  with  copper  nails.  They  shall  be  well 
locked  together,  lay  smoothly,  and  no  attempt  shall  be  made  to 
stretch  the  courses.  The  tile  must  be  laid  so  that  the  vertical  lines 
are  parallel  with  each  other,  and  at  right  angles  to  the  eaves. 

The  tiles  that  verge  along  the  hips  shall  be  fitted  close  against 
the  hip  board,  and  a  watertight  joint  made  by  cementing  the  cut  hip 
tile  to  the  hip  board  with  a  good  elastic  cement.  Each  piece  of  hip 
roll  shall  then  be  nailed  to  the  hip  board,  and  the  hip  rolls  cemented 
where  they  lap  each  other.  The  interior  spaces  of  the  hip  and  ridge 
rolls  must  not  be  filled  with  pointing  material. 

The  tiles  shall  be  of  the  pattern  known  as  (brand  of  tile  and  name 
of  manufacturer  here  mentioned).  The  tile  as  specified  above  must  be 
of  shale,  hard  burned,  and  of  (insert  color  desired)  color.  All  hip  and 
valley  tile  shall  be  cut  to  the  proper  angle  before  burning. 

Remarks.  The  above  specifications  are  applicable  to  pitched 
roofs  only.  It  does  not  emphasize  the  importance  of  the  felt  layer 
underlying  the  tiles.  The  one  defect  of  tile  roofing  is  that  it  is  sub- 
ject to  breakage,  and  when  this  happens  almost  sole  dependence  for 
continued  watertightness  (until  the  tile  is  replaced)  is  upon  the  felt. 
Therefore  the  felt  should  be  applied  with  care,  and  be  of  the  elastic, 
built-up,  membrane  type,  that  is,  consist  of  at  least  two  plies 
cemented  and  properly  nailed  down.  The  grade  and  hardness  of  the 
pitch  or  asphalt  used,  as  binder,  must  also  be  considered.  A  good 
feature  is  that  it  permits  the  selection  and  use  of  many  patterns  of 
tile. 

Composition  Roofing  Method.  (A)  Over  Board  Sheathing* 
Lay  one  (1)  thickness  of  sheathing  paper  or  unsaturated  felt  weigh- 
ing not  less  than  five  (5)  pounds  per  one  hundred  (100)  square  feet, 
lapping  the  sheets  at  least  one  (1)  inch..  See  Fig.  113. 

Over  the  entire  surface  lay  two  (2)  plies  of  tarred  felt,  lapping 
each  sheet  seventeen  (17)  inches  over  preceding  one,  and  nail  as 
often  as  is  necessary  to  hold  in  place  until  remaining  felt  is  laid. 

Coat  the  entire  surface  uniformly  with  coal-tar  pitch. 

Over  the  entire  surface  lay  three  (3)  plies  of  tarred  felt,  lapping 
each  sheet  twenty-two  (22)  inches  over  preceding  one,  mopping  with 
coal-tar  pitch  the  full  twenty-two  (22)  inches  on  each  sheet,  so  that 
in  no  place  shall  felt  touch  felt.  Such  nailing  as  is  necessary  shall 
be  done  so  that  all  nails  will  be  covered  by  not  less  than  two  (2) 
plies  of  felt. 

*  This  specification  should  not  be  used  where  roof  incline  exceeds  three  (3) 
inches  to  one  (1)  foot. 


308 


WATERPROOFING  ENGINEERING 


FIG.  113.— Details  of  Built-up  Slag  Roof  over  Board  Sheathing. 


WATERPROOFING  SPECIFICATIONS  309 

Spread  over  the  entire  surface  a  uniform  coating  of  pitch,  into 
which,  while  hot,  embed  not  less  than  four  hundred  (400)  pounds 
of  gravel  or  three  hundred  (300)  pounds  of  slag  to  each  one  hundred 
(100)  square  feet.  The  gravel  or  slag  shall  be  from  one-quarter  (f) 
to  five-eighths  (f )  inch  in  size,  dry  and  free  from  dirt. 

The  roof  may  be  inspected  before  the  gravel  or  slag  is  applied 
by  cutting  a  slit  not  less  than  three  (3)  feet  long  at  right  angles  to 
the  way  the  felt  is  laid.  All  felt  and  pitch  shall  bear  the  manufac- 
turer's label. 

(B)  Over  Concrete.*  1.  Coat  the  concrete  uniformly  with  hot 
pitch,  see  Fig.  114. 

2.  Over  the  entire  surface  lay  two  (2)  plies  of  tarred  felt,  lapping 
each  sheet  seventeen  (17)  inches  over  preceding  one,  mopping  with 
coal-tar  pitch  the  full  seventeen  (17)  inches  on  each  sheet,  so  that  in 
no  place  shall  felt  touch  felt. 

3.  Coat  the  entire  surface  uniformly  with  pitch. 

4  and  5.  Same  as  for  waterproofing  roofs  over  board  sheathing. 

Remarks.  The  above  specifications  are  equally  applicable  to 
roofs  waterproofed  with  asphalt-treated  felt  and  asphalt  binder. 
For  best  result,  with  built-up  roofings,  both  the  coal-tar  pitch  and 
the  asphalt  must  be  carefully  selected,  as  other  than  the  best  grades 
of  these  materials  are  very  vulnerable  to  the  weather. 

The  Tin  Roofing  Method,  f  All  of  the  tin  used  for  roofing  all 
parts  of  a  building  shall  be  tinned  iron  sheets,  which  shall  be  stamped 
with  the  brand  and  thickness  on  each  sheet. 

All  tin  used  for  standing  seam  roofing  shall  be  ICt  thickness, 
14  by  20  inches,  applied  with  the  14-inch  face  parallel  to  the  eaves, 
forming  seams  with  a  double  lock.  All  tin  for  standing  seam  roofing 
shall  be  put  together  in  rolls  with  the  cross  seams  formed  and 
soldered,  same  as  specified  for  flat  seam  roofing. 

All  standing  seam  roofing  shall  be  fastened  to  roof  with  2-inch 
wide  tin  cleats,  spaced  8  inches  apart,  with  cleats  locked  into  seams, 
and  each  cleat  fastened  with  two  1-inch  barbed  wire  nails. 

All  tin  used  for  flat  roofing  shall  be  1C  thickness,  14  by  20  inch 
size,  using  flat  seams,  with  f-inch  lock.  Flat  seam  roofing  should 

*  This  specification  should  not  be  used  where  roof  incline  exceeds  three  (3) 
inches  to  one  (1)  foot,  and  when  incline  exceeds  one  (1)  inch  to  one  (1)  foot,  the 
concrete  must  permit  of  nailing  or  nailing  strips  must  be  provided. 

t  Richey's  "  Building  Mechanics'  Ready  Reference." 

t  Plates  are  made  in  two  weights,  1C  and  IX.  The  1C  is  No.  30  gauge, 
and  weighs  0.5  pound  to  the  square  foot.  The  IX  is  No.  28  gauge,  and  weighs 
0.625  pound  per  square  foot.  Either  grade  is  suitable  for  either  flat  or  standing 
seam  roofing. 


310 


WATERPROOFING  ENGINEERING 


.Pitch 
•  Pitch* 


•  Felt 
Felt 


•Pitch^  Felt 
Pitch 


Felt 


FIG,  114.— Details  of  Built-up  Slag  Roof  over  Concrete  Slab. 


WATERPROOFING  SPECIFICATIONS  311 

be  made  up  and  soldered  in  the  shop  in  long  lengths,  which  must  be 
painted  on  under  side  with  one  coat  of  paint  and  allowed  to  dry 
before  applying  to  the  roof.  All  flat-seam  roofing  shall  be  fastened 
to  roof  with  2-inch  wide  flat  tin  cleats,  spaced  8  inches  apart,  with 
cleats  locked  into  seams,  and  each  cleat  nailed  to  roof  with  two  1-inch 
barbed  wire  nails.  When  the  rolls  of  tin  are  laid  on  roof  the  edges 
shall  be  turned  up  \  inch  at  right  angles  to  roof,  when  the  cleats  shall 
be  installed.  Then  another  course  shall  be  applied  with  J-inch 
upturned  edge,  the  adjoining  edges  shall  be  locked  together,  and  the 
seam  so  formed  shall  be  flattened  to  a  rounded  edge  and  well  soldered 
and  soaked  in. 

All  valleys  shall  be  formed  with  flat  seam  roofing,  using  14  by  20 
inch  sheets  laid  in  the  narrow  way,  with  cross  seams  put  together  and 
well  soldered,  same  as  specified  for  flat  roofing. 

All  flat  seams  throughout  the  roof,  including  such  other  parts  as 
may  need  soldering  to  make  perfectly  watertight,  shall  be  soldered 
with  best  grade  of  guaranteed  half-and-half  solder  (half  tin  and  half 
lead),  using  nothing  but  rosin  as  a  flux.  Not  less  than  2  pounds  of 
solder  shall  be  used  per  square  on  standing  seam  roofing,  and  not  less 
than  8  pounds  per  square  on  flat  seam  roofing,  all  to  be  well  sweated 
into  the  joints. 

All  rosin  used  in  soldering  must  be  carefully  cleaned  off  from  all 
surfaces  before  any  paint  is  applied  to  the  tin. 

All  tin  shall  be  painted  one  coat  on  concealed  or  under  side,  as 
heretofore  specified,  and  two  coats  on  all  exposed  surfaces:  the  first 
coat  shall  be  given  four  weeks  to  dry  before  the  second  coat  is  applied. 
All  paint  shall  be  applied  with  hand  brushes  and  well  rubbed  in. 
Litharge  only  shall  be  used  as  a  drier.  No  patent  drier  or  turpen- 
tine is  to  be  used.  The  first  coat  on  upper  surface  shall  be  applied 
as  soon  as  laid,  and  the  tin  must  not  be  permitted  to  rust  before 
painting. 

Specification  for  Waterproofing  Railroad  Station  Roof.*  All 
roofs  in  connection  with  the  station  buildings  shall  be  made 
absolutely  watertight  and  weatherproof  with  (name  of  manufacturer) 
"  Built-up  Asbestos  Roofing  "  or  equal  thereto. 

The  asphalt  shall  be  (name  of  brand)  or  equal  thereto  and  shall 
be  applied  sufficiently  hot  to  flow  freely. 

The  felt  shall  be  asphalt-saturated  asbestos  felt  (name  of  brand) 
or  equal  thereto. 

The  parapet  walls,  plumbing  pipes,  smoke  pipes,  etc.,  to  a  height 
of  not  less  than  4  inches,  the  lower  edge  of  the  main  roofs  and  all 
*  New  York  Municipal  Railway  Corporation,  Brooklyn,  N.  Y. 


312  WATERPROOFING  ENGINEERING 

roofs  at  the  walls  and  pipes  to  a  width  of  not  less  than  12  inches 
shall  be  thoroughly  mopped  with  asphalt  and  therein,  while  it  is 
still  hot,  shall  be  embedded  one  thickness  of  felt  to  which  a  second 
thickness  of  felt  shall  be  thoroughly  wiped  with  hot  asphalt.  The 
two  thicknesses  shall  be  not  less  than  4  inches  high  on  the  walls  and 
pipes  nor  less  than  12  inches  wide  on  the  roofs  and  shall  be  applied 
before  the  flashings  and  roof  boxes  are  set  in  place. 

After  the  copper  flashings  and  roof  boxes  have  been  set  and  the 
leaders  connected,  the  surface  of  the  roofs  shall  be  covered  with  not 
less  than  three  thicknesses  of  felt  laid  10 J  inches  to  the  weather, 
thoroughly  embedded  and  wiped  down  in  hot  asphalt  and  well  wiped 
to  the  flashings  and  leader  boxes,  the  felt  to  be  rolled  close  behind 
the  mop  so  that  no  missing  of  hot  asphalt  can  possibly  take  place. 

The  entire  surface  shall  be  finished  to  a  smooth,  even  surface  with 
a  heavy  coat  of  (name  of  manufacturer)  "  Asphalt  Roof  Coating  " 
or  equal  thereto. 

All  flashings  and  cap  flashings  in  any  way  required  to  make  the 
entire  work  absolutely  weathertight  shall  be  furnished  as  a  part  of  the 
work  under  this  section. 

The' flashings,  cap  flashings,  and  roof  boxes  shall  be  made  of  16- 
ounce  cold  rolled  copper  except  the  flashings  and  cap  flashings  to  the 
smoke  pipes  which  shall  be  20-ounce  cold  rolled  copper. 

The  mason  shall  be  furnished  the  cap  flashings  to  be  built  into  the 
concrete;  -these  are  to  be  8  inches  wide  and  built  2  inches  into  the 
concrete  with  the  built-in  edge  turned  up  \  inch;  they  are  to  be  set 
not  less  than  8  inches  above  the  roof  and  where  stepped  should  be 
lapped  not  less  than  the  height  of  the  step. 

The  flashings  shall  be  turned  4  inches  under  the  roofing  and  shall 
be  of  sufficient  width  to  fit  closely  under  the  built-in  portion  of  the 
cap  flashings ;  they  are  to  be  set  after  two  layers  of  roofing  have  been 
applied  as  hereinbefore  specified,  and  the  cap  flashings  are  to  be  bent 
down  and  heavily  tinned  and  soldered  at  all  corners  and  angles. 

All  soldering  in  any  way  required  to  make  the  entire  work  abso- 
lutely watertight  and  weatherproof,  shall  be  done  in  the  neatest  and 
best  manner.  The  copper  which  is  to  be  soldered  shall  be  heavily 
tinned  and  all  joints  shall  be  thoroughly  sweated  and  neatly  soldered 
over  and  all  superfluous  solder  shall  be  neatly  removed. 

All  sheet  metal  work  and  roofing  shall  be  delivered  at  the  final 
completion  of  the  works,  clean,  whole,  perfect,  and  absolutely  water- 
tight and  waterproof. 


CHAPTER  IX 
PRACTICAL   RECIPES   AND    SPECIAL  FORMULAS 

ORIGIN  AND  NATURE  OF  SPECIAL  FORMULAS 

CONSIDERING  the  many  varied  purposes  and  conditions  under 
which  the  different  systems  of  waterproofing  are  found  serviceable, 
it  is  surprising  how  few  are  the  basic  waterproofing  compounds  in 
common  use.  Not  more  than  fifty  of  such  compounds  are  in  the 
market.  Of  these  compounds  the  integral  system  claims  about 
30  per  cent,  the  surface  coating  system  about  40  per  cent,  and  the 
membrane  and  mastic  systems  about  30  per  cent.  The  grouting  and 
self-densified  processes  are  not  considered  in  this  connection  because 
they  require,  besides  a  good  grade  of  material,  only  scientific  manipu- 
lation for  successful  work.  The  general  nature  of  most  of  the  basic 
compounds  is  discussed  in  Chapter  V.  On  the  other  hand,  of  the 
special  waterproofing  compounds  there  are  at  least  several  hundred. 
The  nature  of  these,  of  course,  is  in  most  instances  kept  as  a  trade 
secret.  Still,  from  time  to  time,  some  chemists  and  engineers  dis- 
cover or  invent  useful  waterproofing  compounds  or  new  processes 
for  utilizing  old  compounds.  These  are  often  published  in  the 
technical  press  of  both  the  chemical  and  engineering  professions. 
Government  chemists,  and  engineers  in  particular,  are  very  resource- 
ful and  liberal  in  this  regard.  The  United  States  Department  of 
Agriculture,  the  Department  of  Interior  and  the  Department  of 
Commerce  and  Labor,  publish  annually  scores  of  bulletins  and  tech- 
nical papers  some  of  which  are  replete  with  valuable  information, 
suggestions,  and  tests  on  new  and  old  waterproofing  methods  and 
materials,*  which  are  often  distributed  free  and  never  for  more 
than  cost.  These  publications  are  regarded  with  great  favor  and  au- 
thority in  the  waterproofing  industry;  and  well  they  may  be,  for  they 

are  always  unbiased,  truthful  and  practical,  the  only  adverse  criticism 

• 

*  As  illustrations  of  the  types  of  these  papers,  see  Bulletin  No.  230  of  the  Office 
of  Public  Roads,  U.  S.  Department  of  Agriculture;  Technologic  Paper  No.  3 
of  the  Bureau  of  Standards,  Department  of  Commerce  and  Labor;  Bulletin  No. 
329  of  the  U.  S.  Geological  Survey,  Department  of  Interior. 

313 


314  WATERPROOFING  ENGINEERING 

being  occasioned,  in  a  few  instances,  by  the  occasional  incompleteness 
of  the  data  and  the  results  based  thereon. 

Waterproofing  formulas,  like  paint  formulas,  are  often  individual 
secrets,  kept  by  the  discoverer  from  the  world  for  his  commercial 
advantage.  Like  most  paints,  waterproofing  compounds,  unless 
investigated  by  the  most  competent  chemists,  often  baffle  chemical 
analysis,  and  more  often  chemical  synthesis.  The  method  of  com- 
bining, or  the  process  of  manufacturing  most  waterproofing  com- 
pounds, is  more  difficult  and  kept  more  secretive  than  is  the  knowl- 
edge of  the  constituent  ingredients.  Of  course,  where  compounds 
are  patented,  a  certain  amount  of  information  is  divulged  to  the 
public,  but  the  patent  prevents  the  unlicensed  use  of  the  compounds. 
This  facilitates  and  sometimes  encourages  the  marketing  of  imita- 
tions, better  or  worse,  which  the  purchaser  must  guard  against  by 
careful  investigation. 

In  compiling  this  chapter  the  author  has  freely  availed  himself  of 
all  the  above-mentioned  sources  with  due  acknowledgment.  In- 
cluded also  are  formulas  and  practical  recipes  derived  from  personal 
experience  and  the  experience  of  a  few  associates  in  both  the 
chemical  and  engineering  professions.  In  making  compounds  from 
any  of  these  formulas,  care  and  judgment  are  essential  to  success. 
They  are  arranged  under  the  general  heads  of  Masonry  Treatments, 
Treatments  for  Tanks,  Floor  Treatments,  Roofings,  and  Water- 
proof Cements,  but  no  strict  divisions  were  attempted. 


MASONRY  TREATMENTS 

Waterproof  Mortar.  For  masonry  joints:  equal  parts  of  sand 
and  cement  with  sufficient  water  to  form  a  plastic  paste  produces  a 
very  waterproof  mortar;  for  surfacing  and  stucco  work  a  1  :  2 
mortar  is  very  efficient  provided  it  is  allowed  to  dry  very  slowly. 
A  mixture  consisting  of  one-sixth  underburnt  and  one-sixth  well- 
burnt  powdered  brick,  one-third  slaked  lime,  and  one-third  sand, 
will  make  a  dense,  waterproof  mortar. 

Dampproof  Coating  Compounds  for  Masonry.  An  easily  made 
and  applied  coating  for  dampproofing  purposes  consists  of  about 
20  per  cent,  by  weight,  of  paraffin  (melting-point  between  104  and 
122  deg.  Fahr.  (40  and  50  deg.  Cent.)  dissolved  in  80  per  cent  of  a 
petroleum  oil  mixture.  This  mixture  may  be  made  of  about  45  per 
cent  benzene,  25  per  cent  wood  turpentine  and  30  per  cent 
kerosene. 


PRACTICAL  RECIPES  AND  SPECIAL  FORMULAS  315 

A  similar  compound  can  be  made  by  mixing  about  5  per  cent,  by 
weight,  of  paraffin,  5  per  cent  alumina  resinate,  45  per  cent  benzine 
and  45  per  cent  kerosene. 

A  good  surface-coating  compound  can  be  made  in  the  form  of  a 
thin  paste  by  mixing  with  water  to  the  required  consistency,  about 
96  per  cent  by  weight  of  powdered  cast  iron  and  4  per  cent  of  sal- 
ammoniac.  This  paste  should  be  carefully  applied,  preferably  in 
two  coats  with  a  stiff  brush,  as  it  is  necessary  for  it  to  adhere  to  the 
concrete  to  be  effective. 

A  solution  of  water  glass  (about  5  per  cent)  when  applied  as  a 
coating  to  a  surface  containing  lime  will  form  a  hard,  impervious 
finish  by  the  chemical  action  between  the  lime  and  the  alkaline 
silicate  or  water  glass.  On  concrete  it  is  rather  difficult  to  accomplish 
this  action  because  the  lime  is  not  free  to  get  at. 

Surface  Coatings  for  Masonry.  A  liquid,  waterproof,  surface 
coating,  consists  of  the  following  formula:  70  per  cent  of  asphalt, 
30  per  cent  of  turpentine  substitute  or  other  petroleum  product. 
The  petroleum  product  should  be  added  while  the  asphalt  is  hot. 
The  mixture  can  then  be  applied  cold  with  a  brush.  It  may  also  be 
mixed  as  an  integral  compound  in  mass  concrete  or  mortar  in  quanti- 
ties ranging  between  5  and  10  per  cent  by  weight  of  cement. 

A  plastic  form  of  waterproof  surface  coating  may  be  made  as 
follows:  Pine  creosote  oil,  about  40  per  cent;  fiber  asbestos,  30  per 
cent;  pine  pitch  30  per  cent.  The  pitch  and  oil  must  be  cooked 
together  and  the  asbestos  added  while  the  mixture  is  hot.  This 
material  is  viscous  enough  to  be  troweled  on  the  masonry  and  can 
be  applied  to  a  wet  or  dry  surface. 

A  durable,  tough,  and  elastic  compound  that  can  be  used  for 
both  roof  coverings  and  flashings  consists  of  a  good  grade  of  refined 
asphalt  mixed  with  from  5  to  25  per  cent  of  stearine  pitch.  The 
proportion  is  governed  by  the  consistency  desired  and  the  melting- 
point  of  the  asphalt. 

The  following  surface  coating  will  remain  plastic  and  elastic  for 
a  long  time.  It  is  applied  cold,  by  troweling  on  the  surface  to  be 
waterproofed.  Hot  elaterite,  about  85  per  cent;  mixed  with  about 
15  per  cent  of  castor  oil  or  cotton-seed  oil.  If  a  little  gutta  percha  is 
added,  the  compound  is  considerably  improved. 

An  impervious  surface  coating  for  industrial  concrete  wash  basins, 
etc.,  can  be  obtained  by  rubbing  the  inside  surface  with  a  cement 
brick  just  after  removing  the  forms.  This  brick  can  be  made  of  a 
1  :  2  mortar.  While  rubbing,  the  concrete  surface  should  be  sprinkled 
constantly  with  water;  this  will  form  a  paste  over  the  surface  and 


316  WATERPROOFING   ENGINEERING 

tend  to  fill  the  pores.  Two  or  three  rubbings  in  this  manner  will 
produce  a  very  impervious  surface. 

Dampproofing  for  Brick  Walls.*  In  applying  the  following  com- 
pounds all  dampness  of  the  wall  must  first  be  allowed  to  dry  up  as 
much  as  possible.  The  process  of  dampproofing  then  proceeds  as 
follows:  One  coat  of  boiled  linseed  oil  is  first  applied  over  the  wall 
and  all  joints.  All  holes  are  then  puttied  up  with  a  paste  composed 
of  pure  linseed  oil  and  whiting,  colored  with  fine  brick  dust  or  Vene- 
tian red.  Venetian  red,  thinned  with  equal  parts  of  boiled  linseed 
oil  and  turpentine,  is  then  applied  as  a  second  coat.  Finally  a  third 
coat  of  red  oxide  and  drier  is  applied  as  a  finish  coat.  The  color 
may  be  changed  from  a  red  to  any  desirable  tint  using  white  lead  as 
the  base,  tinting  with  oil  color  to  suit. 

Another  formula  is  as  follows:  Venetian  red  mixed  with  skim 
milk  (casein) .  The  action  of  the  lime  base  in  the  Venetian  red  will 
make  the  curd  of  the  milk  insoluble  in  water.  Should  the  Venetian 
red  be  free  from  lime,  then  lime  water,  whiting  or  quick  lime  must 
be  added  to  the  milk  before  mixing  the  Venetian  red  with  it.  (To 
ascertain  whether  the  Venetian  red  contains  whiting  or  lime,  a  portion 
of  it  is  dropped  in  some  commercial  sulphuric  acid,  and  if  the  red 
powder  does  not  effervesce,  lime  in  the  form  needed  is  not  present, 
and  the  aforesaid  alkaline  addition  must  be  made.)  If  the  color 
is  to  be  waterproofed,  however,  to  each  gallon  thereof  must  be  added 
one-half  gallon  boiled  linseed  oil  and  well  stirred.  Both  these  mix- 
tures, when  properly  made,  will  not  wash  off  for  years. 

A  water-shedding,  dampproofing  compound  for  brick  and  con- 
crete masonry  may  be  made  by  mixing  about  80  per  cent  of  kerosene 
with  10  per  cent  of  acetone  and  10  per  cent  of  creosote.  This  com- 
pound should  be  applied  with  a  brush  and  thoroughly  rubbed  in  on 
a  clean  surface.  It  tends  to  fill  the  pores  of  the  masonry  and  shed 
water  from  the  surface. 

A  damp-resisting  paint  can  be  made  by  mixing,  until  solution  is 
effected,  melted  Manila  or  Copal  gum  with  linesed  oil  or  China  wood 
oil ;  this  mixture  is  then  dissolved  in  benzol  or  naphtha.  It  is  applied 
with  a  brush  in  several  coats.  For  a  top  coat  it  is  well  to  evaporate 
more  of  the  gum  and  add  more  of  the  drying  oil.  The  compound 
may  also  be  mixed  with  any  desired  pigment. 

Stone  Preserving  Compositions.!  With  the  following  liquid 
compound  it  is  possible  to  preserve  a  brownstone  front  against  the 

*  "  739  Paint  Questions  Answered,"  published  by  The  Painters'  Magazine  of 
New  York  in  1904. 

t  "  Scientific  American  Cyclopedia  of  Formulas,"  1915. 


PRACTICAL  RECIPES  AND  SPECIAL  FORMULAS  317 

weather  without  altering  its  appearance,  its  stony  aspect  not  being 
altered  by  the  liquid  after  it  has  penetrated  and  dried.  Ten  gallons 
of  thinning  liquid,  such  as  fish  oil,  or  linseed  oil,  mixed  with  2  pounds 
dry  zinc  white,  and  5  pounds  powdered  brown  oxide.  Before  apply- 
ing the  liquid,  the  surfaces  should  be  brushed  clean  with  wire  brushes. 

Paraffin  is  the  best  material  for  rendering  natural  stones,  con- 
crete and  brick-work  impervious  to  water.  If  dissolved  in  the  pro- 
portion of  one-third  paraffin  and  two-thirds  kerosene,  it  remains 
soft  longer  and  penetrates  the  stone  further.  Paraffin  is  unaltered 
by  weather  or  acids.  If  carefully  melted  in,  it  does  not  change  the 
color  of  the  stone;  it  simply  deepens  the  color  like  water.  It  is 
cheap,  easily  applied  and  efficacious.  It  is  most  easily  applied  in 
hot  weather. 

Leaks  in  concrete  walls  can  be  stopped  by  enlarging  the  cracks 
and  applying  a  hot  mixture  of  Portland  cement  and  caustic  soda, 
which  sets  almost  instantly.  The  concrete  around  the  leak  should 
be  cut  out  so  that  the  hole  or  groove  is  larger  at  the  base  than  at  the 
surface.  The  hot  paste  is  then  applied  rapidly  with  gloved  hands, 
first  against  one  side  of  the  cavity  and  then  successively  around  the 
sides  of  the  cavity  until  it  is  completely  closed.  The  soda  should 
be  mixed  with  little  water  and  be  boiling  hot  when  the  cement  is 
added  in  amounts  enough  to  make  a  stiff  paste.* 

TREATMENT  FOR  TANKS 

Preserving  Concrete  Tanks  from  Cemmercial  Liquids,  f    The 

following  fluids  may  be  stored  in  tanks  made  of  plain  dense  con- 
crete of  1  :  2  :  4  mix  without  causing  any  deterioration  in  the  con- 
crete: Menhaden  oil,  linseed  oil,  rosin  oil,  4  per  cent  caustic  soda 
solution,  tanning  solution,  and  sauerkraut. 

For  safely  storing  sulphite  liquor  and  cider  vinegar  in  concrete 
tanks,  the  only  satisfactory  method  found  to  protect  the  concrete 
from  disintegration  is  by  applying  a  surface  coat  of  an  oil-gilsonite 
compound.  This  compound  is  made  by  dissolving  100  parts,  by 
weight,  of  gilsonite  in  250  parts  of  turpentine,  and  adding  5  parts 
of  neutral  petroleum  oil.  At  ordinary  temperatures,  with  frequent 
stirring,  about  twenty-four  hours  will  be  required  for  a  perfect 

*  Engineering  Record,  March  3,  1917. 

t  Results  of  a  series  of  tests,  extending  over  a  period  of  more  than  a  year, 
made  for  the  Portland  Cement  Association  to  determine  the  effects  of  commercial 
liquids  on  concrete  tanks,  by  the  Institute  of  Industrial  Research,  Washington, 
D.  C,  Reported  in  Engineering  Record,  Vol.  74,  No.  16,  October  14,  1916. 


318  WATERPROOFING  ENGINEERING 

solution.  Two  coats  of  this  mixture,  should  be  applied  with  a  brush 
to  the  inner  surface  allowing  at  least  twenty-four  hours  for  each 
to  dry. 

For  safely  storing  molasses  in  concrete  tanks,  in  a  manner  so  that 
neither  the  molasses  nor  the  concrete  is  injured,  the  inner  surface 
should  be  well  protected  with  two  coats  of  Bakelite  varnish.  Con- 
centrated brines  may  similarly  be  stored  in  concrete  tanks  by  coat- 
ing the  inside  with  two  layers  of  the  above-mentioned  oil-gilsonite 
compound  between  which  is  placed  an  asphalt-treated  fabric. 
Upon  this  one-ply  membrane  should  be  placed  a  1  :  2  cement  mortar 
coating,  and  the  latter  painted  with  two  coats  of  Bakelite. 

Cement  to  Resist  Benzine  and  Petroleum.*  Gelatine  mixed 
with  glycerine  yields  a  liquid  compound  when  hot,  but  which 
solidifies  on  cooling,  and  forms  a  tough,  elastic  substance,  having 
much  the  appearance  and  characteristics  of  India  rubber.  The 
two  substances  unite  to  form  a  mixture  absolutely  insoluble  in  pe- 
troleum or  benzine,  and  the  problem  of  making  casks  impervious  to 
these  fluids  may  be  solved  by  brushing  or  painting  them  on  the 
inside  with  this  compound.  Water  must  not  be  used  with  this 
compound. 

Wooden  and  Iron  Tanks  Made  Watertight.  Wooden  tanks  should 
first  be  drained  well  and  permitted  to  dry  out  thoroughly.  Then 

the    hoops   must  be  tightened  and 
the  inside  be  given  a   coat   or  two 
of  hot  paraffin  oil  or  melted  paraffin 
wax,  applied  while  hot.     This  done, 
the  iron  or  steel  hoops  should  receive 
a  coat  of  red  lead  and  the  outside  of 
the  tank  one  or  two  coats  of  good, 
elastic  oil  paint  of  any  color  desired,  f 
Joints  in  iron    tanks   that  have 
opened  up  can  be  sealed  effectively 
by  calking  with    proper   tools    (see 
Fig.   115).      This  operation  consists 
FIG.  115.— Calking  Operation  with  in   beating  down  the   edges    of  the 
Hand    or    Pneumatic     Calking  metal  against  the  face  of  the  opposite 
Tools-  plate.       The     round -nosed    calking 

tool  is  usually  employed  in  modern 
practice.     A  more  effective  way  of  calking  is  with  lead  wool  hammered 

*  "  Scientific  American  Cyclopedia  of  Formulas,"  1915. 
t  "  739  Paint  Questions  Answered,"   published  by  The  Painters'    Magazine 
of  New  York  in  1904, 


PRACTICAL   RECIPES  AND  SPECIAL  FORMULAS  319 

into  the  joint.  Coating  the  outside  of  the  joint  with  a  thick  applica- 
tion of  a  hard,  tough  asphalt  or  a  sealing  w.x  of  a  similar  nature, 
is  also  effective  except  for  hot-water  tanks.  Both  of  these  materials 
must  be  applied  on  a  properly  cleaned  surface. 

A  preserving  varnish  for  wood  and  metal  tanks  is  easily  made  by 
mixing  three  parts  of  pure  asphalt  (solid  or  liquid  variety)  with  four 
parts  of  boiled  linseed  oil  and  from  fifteen  to  eighteen  parts  of 
turpentine. 

FLOOR  TREATMENTS 

Concrete  Floor  Hardener.  The  following  formula  is  used  for 
hardening  concrete  floors:  Powdered  pig  iron  mixed  with  about 
2  per  cent,  by  weight,  of  salammoniac.  This  mixture  may  be 
floated  on  a  partially  set  concrete  surface  which  is  thereby  hardened 
for  a  depth  of  a  fraction  of  an  inch,  but  it  is  not  very  durable.  The 
mixture  may  also  be  combined  with  Portland  cement  in  equal 
proportions  by  weight  to  form  a  mortar  that  is  applied,  about 
f  inch  thick  on  a  clean  surface  of  concrete.  This  mortar  coat  will 
create  a  dense  and  impervious  floor  if  properly  and  carefully  applied. 
A  serious  objection  to  the  use  of  this  formula  is  the  frequent  discol- 
oration of  the  surfaces  treated  due  to  the  uneven  distribution  and 
oxidation  of  the  powdered  metal. 

Wooden  Floor  and  Flooring  Made  Watertight.*  Flooring 
may  be  made  impermeable  by  being  painted  with  a  solution  of 
paraffin  wax  dissolved  in  kerosene.  The  coat  will  last  for  about 
two  years. 

ROOFINGS 

Roofing  Paner.f  Old  newspapers  or  sheets  of  wrapping  paper 
in  good  condition  may  be  converted  into  waterproof  roofing  material 
by  coating  them  with  hot  coal-tar  pitch  or  asphalt  with  a  brush, 
and  uniting  two  or  more  sheets.  These  mats  can  then  be  applied 
to  a  roof,  shingle  fashion,  creating  a  cheap  but  good  roofing  for  sheds 
and  shanties  and  for  temporary,  small  constructions. 

Roofing  Cement.  A  waterproof  bituminous  cement  for  binding 
roofing  felt,  one  that  will  not  flow  readily  in  the  summer's  heat, 
may  be  made  by  mixing  one  part  of  burnt  lime  (but  not  slaked) 
with  seven  parts  of  coal  tar,  both  by  weight.  The  lime  is  powdered 

*  "  Scientific  American  Cyclopedia  of  Formulas,"  1915. 
t  "  Scientific  American  Cyclopedia  of  Formulas,"  1915, 


320  WATERPROOFING   ENGINEERING 

and  sprinkled  into  the  hot  tar,  with  which  it  mixes  intimately.     The 
mixture  hardens  on  cooling  and  therefore  must  be  applied  hot. 

WATERPROOF  CEMENTS 

Adhesives.  The  following  waterproof  cements  can  be  made  with 
but  little  difficulty  or  previous  experience:* 

(1)  Shellac,  4  ounces;    broax,  1  ounce;    boiled  in  a  little  water 
until  dissolved,  and  concentrated  by  heat  to  a  paste. 

(2)  Carbon   bisulphide,    10   parts;     oil   of   turpentine,    1    part; 
mixed  with   as  much  gutta-percha  as  will  readily  dissolve  in  the 
mixture. 

(3)  Tar,  1  part;    tallow,  1  part;    fine  brick    dust,  1  part;    the 
latter  should  first  be  warmed  over  a  very  gentle  fire;    the  tallow 
added,  then  the  tar,  and  the  whole  thoroughly  mixed.     This  com- 
pound must  be  applied  while  hot. 

(4)  Good  quality  gray  clay,  4  parts;   black  oxide  of  manganese, 
6  parts;    lime,   reduced  to  powder  by  sprinkling  with  water,   90 
parts;  the  combination  mixed,  calcined  and  powdered. 

(5)  A  very  strong  cement,  but  one  which  requires  to  be  applied 
directly  after  being  made  as  it  sets  very  quickly,  is  the  following: 
Quicklime,  5  parts;   fresh  cheese,  6  parts;  water,  1  part.     The  lime 
is  slaked  by  sprinkling  with  water;   thereupon  it  is  passed  through 
a  sieve,  and  the  fresh  cheese  is  added.     The  latter  is  prepared  by 
curdling  milk  with  a  little  vinegar  and  removing  the  whey. 

(6)  A  cement  adapted  for  joining  stone,  metal,  wood,  etc.,   can 
be  made  as  follows:  Fresh  curd,  as  before,  1  pert;  Roman  (natural) 
cement,  3  parts.     This  must  be  well  mixed  and  quickly  applied. 

(7)  A  cementing  paste  composed  of  hydraulic  lime  and  dissolved 
water  glass  will  withstand  the  action  of  heat  as  well  as  water. 

(8)  Glue,  1  part;   black  rosin,  1  part;   red  ochre,  }  part;   mixed 
with  the  least  possible  quantity  of  water. 

(9)  Glue,  4  parts;  boiled  linseed  oil,  1  part;  oxide  of  iron,  1  part 
all  by  weight  and  well  mixed  together. 

(10)  A  good  cement  is  made  by  mixing  about  7  parts  of  litharge 
and  93  parts  of  burned  clay  or  whiting  together  reduced  to  a  fine 
powder  and  made  into  a  paste  with  linseed  oil. 

f  (11)  A  cement  may  be  formed  by  mixing  into  a  paste  freshly 
calcined  oyster  shell  lime,  well  sifted  and  ground  fine  with  white  of 
egg- 

*  "  Scientific  American  Cyclopedia  of  Formulas,"  1915. 

t  "  739  Painters  Questions  Answered,"  Painters'  Magazine,  New  York, 


PRACTICAL  RECIPES  AND  SPECIAL  FORMULAS  321 

(12)  Four  parts,  by  weight,  of  shellac  boiled  with   1   part,  by 
weight,  of  borax  in  water  until  the  shellac  is  dissolved.     This  mix- 
ture should  be  kept  boiling  until  it  is  of  a  paste-like  consistency. 
To  use  this  paste  it  must  be  heated  and  applied  with  a  clean  brush. 

(13)  For  many  odd  and  varied  purposes,  commercial  sealing  wax 
will  prove  a  very  good  waterproof  cement.     It  consists  of  hard 
resinous  materials,  such  as  lac,  with  some  form  of  pigment,  as  ver- 
milion.    Beeswax  alone  or  mixed  with  a  fine  mineral  dust  can  also 
be  used  to  advantage. 

Waterproof  Cement  for  Leather.*  A  waterproof  cement  for 
leather  is  prepared  by  dissolving  gutta-percha,  caoutchouc,  benzoin, 
shellac,  mastic  f  and  similar  materials,  in  some  convenient  solvent 
like  carbon  disulphide,  chloroform,  ether  or  alcohol.  The  best 
solvent,  however,  in  the  case  of  gutta-percha  is  carbon  Ksulphide, 
and  ether  for  mastic.  The  most  favorable  proportions  are  as  follows: 
Gutta-percha  200  to  300  parts  to  100  parts  of  the  solvent,  and  75  to 
85  parts  of  mastic  to  100  parts  of  ether.  From  5  to  8  parts  of  the 
foimer  solution  mixed  with  1  part  of  the  latter  and  boiled  in  a  water 
bath  to  any  consistency  desired  makes  a  good  cement. 

Waterproof  Compounds  for  Textile  Fabrics. {  Textile  fabrics 
can  be  made  waterproof  by  successive  impregnations  with  a  solution 
of  soap  and  a  solution  of  alum.  Or,  by  successive  impregnations 
with  a  solution  of  alumina  sulphate  (made  by  dissolving  in  ten  times 
its  weight  of  water),  and  a  soap  solution  composed  of  1  ounce  light- 
colored  rosin,  1  ounce  of  crystallized  soda,  boiled  together  in  10 
ounces  of  water  until  dissolved.  Also  by  impregnation,  first  with  a 
solution  of  ammoniacal  cupric  sulphate  of  10  deg.  Baume  at  77  deg. 
Fahr.  (25  deg.  Cent.)  then,  with  a  solution  of  caustic  soda  of  20 
deg.  Baume.  Increased  impermeability  will  be  obtained  by  using 
sulphate  alumina  in  place  of  caustic  soda.  To  waterproof  one  side 
of  cloth,  it  must  be  imbued  on  the  wrong  side  with  a  solution  of 
isinglass,  alum,  and  soap  in  equal  parts  each  dissolved  separately, 
and  made  into  a  solution  with-  sufficient  water.  Another  method  is 
to  impregnate  the  fabric  with  hot,  molten  paraffin. 

Sheets  of  canvas  or  tarpaulins  may  be  made  waterproof  by  paint- 
ing the  surfaces  with  or  clipping  them  in  a  mixture  of  coal  tar, 
gasoline  and  a  good  Japan  drier  in  the  proportion  of  5  :  1  :  1. 

*  "  The  Manufacture  of  Varnishes  and  Kindred  Industries,"  by  Livache 
and  Mclntosh,  Vol.  3,  p.  376. 

f  A  form  of  resin  secreted  by  shrubby  trees  cultivated  on  the  island  of  Chios 
in  the  Greek  Archipelago. 

J  "  Scientific  American  Cyclopedia  of  Formulas,"  1915,  Munn  &  Co.,  Inc. 


322  WATERPROOFING  ENGINEERING 

Waterproof  Compound  for  Drawing  and  Tracing  Sheets.* 
Drawing  and  tracing  sheets  can  be  made  waterproof,  so  that  they 
may  be  used  in  wet  places,  as  in  mines,  for  instance,  by  the  applica- 
tion, to  one  or  both  sides,  of  a  preparation  composed  of  rubber  and 
benzol.  The  preparation  is  made  by  dissolving  a  quantity  of  pure 
rubber  in  benzol  and  thinning  down  with  more  benzol  to  any  desired 
consistency.  The  rubber  first  swells  enormously  and  in  about 
twenty-four  hours  is  ready  for  use.  For  use  as  a  waterproof  adhe- 
sive the  solution  should  be  fairly  stiff.  Only  the  pure  gum  rubber 
is  satisfactory  for  this  purpose. 

*  Engineering  News-Record,  Vol.  81,  No.  13,  September  26,  1918,  p.  597. 


CHAPTER  X 
WATERPROOFING  APPLIED 

WATERPROOFING  applied  forms  an  important  part  of  waterproof- 
ing engineering  and  also  a  very  interesting  one.  It  describes  accom- 
plishment in  the  field.  Chemical  analyses  and  physical  tests  of 
waterproofing  materials  are  important  but  they  are,  after  all,  mostly 
accelerated  tests.  Service  is  the  real  "  acid  test  "  for  all  waterproof- 
ing materials  and  their  application.  The  best  criterion  of  the  rela- 
tive merits  of  the  various  materials  and  systems  of  waterproofing 
discussed  in  previous  chapters  is  their  efficacy  and  endurance  in 
service.  Many  secret  and  patented  compounds  and  various  types 
of  waterproofing  cannot  be  fairly  judged  in  any  other  way  than  by 
their  past  performences.  In  fact,  certain  grades  of  asphalt  have  won 
favor  and  preferance  for  waterproofing  purposes  by  no  other  means 
than  past  service.  Coal-tar  pitch  is  extensively  used  for  water- 
proofing underground  structures  for  the  same  reason.  On  the  other 
hand,  many  integral  and  surface-coating  compounds  proved  their 
unworth  in  this  manner  though  apparently  successful  in  the  labora- 
tory. The  grouting  process  of  waterproofing  is  advancing  rapidly 
now  only  because  of  its  efficiency  as  proved  in  service. 

In  this  chapter  will  be  found  practical  instances  of  each  of  the 
six  systems  of  waterproofing  previously  discussed ;  also  the  standard 
and  special  materials  used,  the  methods  of  application  and  where 
possible  the  degree  of  success  obtained. 

EXAMPLES  OF  SURFACE  COATING  APPLICATIONS 

Water  Storage  Works,  U.  S.  Reclamation  Service.     The  storage 
works  and  tunnel  connected  with  the  Strawberry  Valley  Project  * 
in  the  U.  S.  Reclamation  Service  are  located  in  the  Wasatch  Moun- 
tains at  an  elevation  of  7500  feet,  surrounded  by  mountains,  some  of 
which  reach  an  elevation  of  10,000  feet  above  sea  level.     There  is  a 
wide  variation  in  temperature  in  this  vicinity  during  the  entire 
*  Enginerring  News,  Vol.  73,  No.  15,  April,  1915. 
323 


324  WATERPROOFING  ENGINEERING 

year,  and  the  climate  is  very  severe  during  the  winter  months,  the 
lowest  temperature  on  record  being  50  deg.  Fahr.  below  zero.  The 
snowfall  ranges  from  10  feet  in  low  years  to  24  feet  in  high  years. 
On  account  of  these  conditions  of  extreme  cold,  with  alternate  thaw- 
ing and  freezing,  the  action  of  water  and  frost  on  concrete  that  is 
not  impervious  is  very  marked.  It  was  therefore  decided  to  treat 
the  concrete  with  some  sort  of  preventive  against  absorption  of  water 
by  the  surfaces  exposed. 

A  study  was  made  of  the  various  waterproofing  processes  in  com- 
mon practice.  Because  the  structures  had  been  completed,  and  in 
view  of  the  extraordinary  conditions,  it  was  decided  to  treat  the  verti- 
cal surfaces  with  alum  and  soap  solutions  (Sylvester  process)  and  the 
horizontal  ones  with  paraffin. 

The  alum  solution  was  made  by  dissolving  2  ounces  of  alum  in 
1  gallon  of  hot  water.  The  soap  solution  was  composed  of  f  pound 
of  castile  soap  dissolved  in  1  gallon  of  hot  water.  The  paraffin 
was  boiled  to  rid  it  of  any  water  content,  as  the  presence  of  water 
rendered  it  hard  to  apply.  Ordinary  commercial  products  were 
used. 

The  surface  to  be  treated  with  paraffin  was  first  entirely  freed  from 
all  moisture,  loose  concrete,  dirt  and  other  foreign  substances.  The 
paraffin  was  then  heated  and  applied  to  the  surface  of  the  concrete 
with  a  paint  brush  and  was  forced  into  the  pores  by  flashing  the 
flame  of  a  blow  torch  over  the  surface. 

In  the  application  of  the  alum  and  soap  (which  produces  an  in- 
soluble aluminum  stearate  in  the  pores  and  on  the  surface  of  the 
concrete),  the  surface  of  the  concrete  was  first  prepared  in  the  same 
manner  as  for  the  paraffin  treatment.  The  alum  solution  was 
then  applied  at  a  temperature  of  100  deg.  Fahr.  with  a  moderately 
stiff  brush,  and  was  then  worked  in  with  a  stiff  horse-brush.  While 
the  surface  was  still  moist  from  this  treatment  the  hot  soap  solution 
was  applied  in  the  same  manner.  One  treatment  with  each  solution 
in  the  manner  described  above  constituted  a  coai.  If  other  coats 
were  deemed  necessary,  they  were  applied  in  a  manner  similar  to  the 
first  coat,  after  the  preceding  coat  had  been  allowed  to  stand  twenty- 
four  hours  or  more.  The  work  of  application  was  carried  on  by  two 
men,  one  applying  the  solution  and  the  other  following  and  working 
it  in  as  described  above. 

No  actual  tests  were  made  to  determine  the  imperviousness  of 
the  concrete  after  treatment,  but  the  structures  that  were  repaired 
and  treated  have  gone  through  two  severe  winters  and  no  further 
disintegration  of  the  concrete  on  any  part*  thereof  has  occurred. 


WATERPROOFING  APPLIED  325 

Gate  Houses  of  Croton  Reservoir.*  In  the  New  York  City 
Croton  Reservoir  the  face  walls  of  the  back  bays  of  gate  houses  were 
built  of  hard-burnt  brick  laid  in  cement  mortar.  A  space  between 
the  walls  4  feet  wide  was  filled  with  concrete.  The  brick  walls  were 
12  inches  thick  and  40  feet  high  and  impounded  water  under  a 
head  of  36  feet.  When  the  reservoir  was  first  filled  and  water  let 
into  the  gate  houses,  it  filtered  through  the  walls  to  a  considerable 
amount. 

The  Sylvester  process  for  repelling  moisture  from  external  walls 
was  used  to  waterproof  the  walls  of  these  gate  houses.  This  con- 
sisted of  two  washes  or  solutions  for  covering  the  surface  of  brick 
walls,  one  composed  of  castile  soap  and  water  and  one  of  alum  and 
water.  The  proportions  were  f  pound  of  soap  to  1  gallon  of  water; 
and  |  pound  of  alum  to  4  gallons  of  water,  both  substances  being 
perfectly  dissolved  in  the  water  before  being  used. 

The  first,  or  soap  wash  was  applied,  at  boiling  heat,  with  a  flat 
brush,  taking  care  not  to  form  a  froth  on  the  brick  work.  This 
wash  remained  twenty-four  hours  so  as  to  become  dry  and  hard 
before  the  second  or  alum  wash  was  applied ;  which  was  done  in  the 
same  manner  as  the  first.  The  temperature  of  this  wash  when 
applied  was  between  60  and  70  deg.  Fahr.  At  least  twenty-four 
hours  elapsed  before  a  second  coat  of  the  soap  wash  was  put  on. 
These  coats  were  repeated  alternately  until  the  walls  were  made  im- 
pervious to  water.  Four  coatings  rendered  the  brick  wall  imperme- 
able under  a  pressure  of  40-foot  head.  The  cost  was  about  ten  cents 
per  square  foot  for  four  coats. 

Retaining  Walls,  Rock  Island  Pailrcad.  The  retaining  walls 
and  abutments  on  the  Chicago  track  elevation  work  of  the  Rock 
Island  Railroad  Lines  are  waterproofed  with  a  coal-tar  pitch  com- 
position applied  to  the  back  of  the  walls.  The  expansion  joints  of 
these  walls  were  waterproofed  by  placing  a  strip  of  burlap  and  felt 
over  each  joint  and  mopped  with  the  same  composition.  Later 
observations  showed  these  coatings  to  be  satisfactory. 

Beaver  Park  Dam.f  The  Beaver  Park  Dam  in  Colorado  is  a 
masonry  structure  of  the  rock-fill  type.  It  was  made  watertight 
by  the  application  of  reinforced  concrete  facing  to  its  upstream 
face,  as  indicated  in  Fig.  116.  This  concrete  face  was  placed  with 
no  rods  or  ties  to  secure  it  to  the  rubble  face  of  the  dam,  as  the 
interstices  in  the  rubble  face  were  depended  upon  to  give  sufficient 

*  Abstract  of  Paper  read  before  the  American  Society  of  Civil  Engineers  by 
Mr.  Wm.  L.  Deardon,  May  4,  1870. 

t  Engineering  News,  Vol.  73,  April  8,  1915. 


326 


WATERPROOFING   ENGINEERING 


bond  between  the  concrete  and  the  hand-laid  wall.  The  concrete 
is  reinforced  horizontally  and  vertically  with  wire  fabric  of  diamond 
mesh,  the  main  wires  being  No.  4  gauge,  spaced  5  inches  apart.  No 
expansion  joints  were  provided,  and  although  the  concrete  face  has 
been  exposed  to  severe  temperature  conditions,  few  or  no  tempera- 
ture cracks  have  occurred. 

The  concrete  in  the  lower  portion  of  the  wall  forming  the  water 
face  and  in  the  gate  tower  was  of  1:2:4  mixture,  the  aggregate 
consisting  of  crushed  trachite,  while  the  upper  portion  of  the  wall 
and  tower  was  made  of  a  mixture  consisting  of  practically  equal  parts 
of  sand  and  gravel.  Up  to  a  point  about  20  feet  below  the  crest, 
a  calcium-oleate  waterproofing  compound  was  added  to  the  water 
used  to  gauge  the  mixture.  The  specifications  provided  that  one  part 


JE1.194    K-16*) 
H.W.L.E1  185 


1  Slope,  Rubble 

Masonry  pointed 

with  Cement  Mortar 


SPILLWAY  SECTION  MAIN   SECTION 

FIG.  116. — Sections  through  Beaver  Park  Dam  Showing  Waterproof  Facings. 

of  the  compound  was  to  be  added  to  an  equal  amount  of  water 
and  thoroughly  dissolved,  after  which  eleven  more  parts  of  water 
were  to  be  added,  and  this  solution  used  in  mixing  the  concrete  for 
all  24-inch  walls  and  a  somewhat  weaker  solution  for  thinner  walls. 
The  results  obtained  by  using  this  compound  seemed  so  unsatis- 
factory to  the  engineer,  that  its  use  was  ordered  discontinued,  and 
extra  cement  was  added  to  the  concrete  at  the  same  cost,  which  gave 
much  better  results. 

Queensboro  (Steinway)  Tunnel.  The  Queensboro  tunnel  in 
New  York  City  (formerly  known  as  the  Steinway  tunnel),  is  about 
80  feet  below  ground-water  level  in  water-bearing  rock.  In  its 
reconstruction  the  stations  were  enlarged  and  waterproofed.  It  was 
proposed  to  waterproof  one  very  large  station  by  the  membrane 
system,  and  two  remaining  small  ones  by  the  surface-mortar-coating 
system.  The  membrane  was  to  consist  of  six  plies  of  treated  fabric 
laid  in  coal-tar  pitch  and  applied  over  the  arch  as  shown  in  Fig.  117. 
For  lack  of  head  room  and  on  account  of  the  great  expense  involved 
in  securing  this  head  room  the  membrane  was  not  installed.  In- 


WATERPROOFING   APPLIED 


327 


stead,  a  waterproofed  surface  mortar-coat  was  applied.  In  1916 
the  two  small  stations  and  a  portion  of  the  very  large  station  were 
treated  with  a  1-inch  mortar  coat,  waterproofed  with  a  proprietary 
liquid  compound  composed  of  a  mixture  of  calcium  chloride  and  a 


Proposed  6  ply  waterproofing 

membrane,  abandoned  for 

lack  of  headroom. 


Pay  line  for 
concrete. 

Net  line 


FIG.  117. — Typical  Half-section  through  Station. 

carbohydrate  and  applied  with  a  trowel  on  the  inside  of  the  arch  and 
sides.  This  surface  mortar  coat  contained  about  7  per  cent  of  the 
waterproofing  liquid  (added  to  the  gauging  water)  was  easy  to  apply 
but  troublesome  after  application,  required  repairing,  and  even  then 
it  did  not  remain  entirely  impervious  thereafter.  In  1917  the  remain- 


328  WATERPROOFING  ENGINEERING 

ing  and  major  portion  of  the  large  station  was  waterproofed  by  the 
application  of  a  similar  mortar  coat  J  inch  thick,  made  of  a  1:2 
mixture  containing  an  alum-soap  paste  compound  mixed  in  the  pro- 
portion of  one  part  paste  to  fifteen  parts  of  gauging  water.  As  a 
result  of  this  work  the  leakage  was  markedly  reduced.  Some  blast- 
ing in  the  vicinity  may  have  contributed  to  the  difficulty  of  making 
these  waterproofed  mortar  coats  entirely  impervious. 

Nashville  Water  Works  Reservoir.  In  repairing  and  water- 
proofing the  Nashville  Water  Works  Reservoir  *  precaution  was 
taken  against  cracks  opening  at  the  junction  of  the  new  masonry 
with  the  old,  by  using  a  flexible  U-shaped,  heavy,  sheet-lead  stop 
joint.  This  was  inserted  by  cutting  a  dove-tail  groove  in  the  con- 
crete core  from  bottom  to  top  of  the  ends  of  the  old  wall,  and  by 
anchoring  one  end  of  the  lead  joint  therein  with  rich  concrete  in 
advance  of  the  new  masonry,  but  leaving  the  other  end  free.  The 
fold  in  the  joint  was  protected  with  tar  felt  to  assure  free  movement, 
and  the  new  masonry  was  built  around  the  free  end  thereof.  This 
contrivance  was  simple,  effective,  of  very  little  trouble,  and  inex- 
pensive. See  Fig.  118.  For  waterproofing  the  interior  face  of  the 
walls,  the  cement  gun  was  used  and  the  work  proceeded  in  the  fol- 
lowing manner:  The  walls  were  first  thoroughly  cleaned  of  all 
scale  and  foreign  matter  by  means  of  pneumatic-hammer  chisels 
so  as  to  afford  sound  stone  faces  for  the  mortar.  By  the  same 
means  the  old  mortar  joints  were  gouged  out  to  depths  varying  from 
1  to  3  inches  for  the  cement-gun  mortar.  The  walls  were  therl 
sinrl-blasted  and  sprayed  immediately  in  advance  of  the  cement- 
gun,  resulting  in  clean,  sound,  stone  faces  and  mortar  joints. 

The  cement-gun  mortar,  composed  of  one  volume  of  Portland 
cement  to  three  volumes  of  clean  sand,  followed  right  behind  the  sand 
blasting  and  •  spraying  before  the  walls  could  dry.  The  whole 
interior  of  the  walls,  including  the  new  masonry,  was  thus  coated 
and  made  watertight. 

Before  laying  the  asphalt-treated  felt  membrane  used  to  water- 
proof the  floor,  the  old  concrete  floor  was  carefully  cleaned  and 
flushed  off  with  a  powerful  stream,  and  all  loose  scale  removed.  All 
rough  places  and  sharp  depressions  were  then  filled  and  brought  to  a 
smooth  plane  with  rich  cement  mortar.  After  thoroughly  drying, 
the  floor  was  well  painted  with  a  priming  coat  of  asphalt  dissolved 
in  naphtha.  This  was  followed  with  a  very  heavy  coat  of  asphalt 
heated  to  a  temperature  of  about  325  deg.  Fahr.  The  asphalt- 
treated  felt  followed  closely  behind  this  mop  coat,  in  alternate  layers 
*  Engineering  News,  Vol.  73,  May  6,  1915. 


WATERPROOFING  APPLIED 


329 


of  felt  and  heavy  mop  coats.  Each  layer  of  felt  was  carefully  rolled 
down  before  the  succeeding  coat  and  next  layer  of  felt  were  applied, 
care  being  taken  to  squeeze  out  all  the  air  bubbles.  The  felt  over- 


6  Ply 


Limestone  facing  stones 
laid  ia  Portland  Cetneut, 
mortar  to  match  exist- 
ing wall 


Broken  stone 

around  i"  Vit. 
drain  laid  with 
open  joints, 
slope  1:100 


All  reinforcing  rods  to   Theoretical  inside 


;o  /Theoretical  in 
J  line  of  wall 
I  i"  A^////^/ 


(Theoretical  inside 
VJ  Hne  of  wall 

71., /     '//////. 


30.  toC. 

_     g  £        Asphalt 

Is 


SECTION  SHOWING    WEDGE 
JOINT  AT  OUTSIDE  WALL 


SECTION  SHOWING 
JOINT  AT  DIVISION  WALL 


FIG.   118. — Showing  Waterproofing  Details  of  Nashville  Reservoir  Wall  and 

Floor. 

lapped  and  broke  joints  3  inches  on  longitudinal  edges  and  10  or 
12  inches  on  ends.  Five  layers  of  the  felt  were  employed,  ending 
with  a  heavy  mop  coat  all  over  the  top. 


330  WATERPROOFING  ENGINEERING 

The  reservoir,  repaired  as  above  described,  was  for  all  practical 
purposes  watertight  for  over  two  years.  In  May,  1916,  it  was 
emptied  during  the  warm  weather  for  cleaning.  During  the  process 
of  cleaning  and  removing  the  mud  out  of  the  basin,  the  cement-gun 
mortar  was  exposed  to  the  sun's  rays,  and  badly  checked  and  cracked. 
These  defects  were  corrected  by  cutting  the  mortar  out  of  all  visible 
checks  and  cracks  to  the  original  masonry.  These  cut-out  cracks 
were  then  rilled  with  cement  gun-mortar.  A  water  curtain  was 
then  provided  to  sprotect  the  walls  from  the  effect  of  the  sun's  rays. 
This  was  accomplished  by  means  of  a  perforated  pipe  kid  around 
the  inner  edge  of  the  top  of  the  wall,  from  which  the  water  trickled 
down  and  spread  over  the  mortar  lining.  By  these  means,  the  basin 
was  again  made  watertight. 

The  Hudson-Manhattan  Tunnels.*  Wherever  work  was  executed 
by  open-cut  methods  on  the  Hudson-Manhattan  Tunnels,  between 
New  York  and  New  Jersey,  the"  structure  was  waterproofed  with 
treated  fabric  and  coal-tar  pitch  applied  in  the  usual  manner,  making 
a  complete  envelope  around  it.  As  the  greatest  part  of  this  work, 
however,  was  executed  by  tunnel  methods  this  manner  of  waterproof- 
ing was  not  feasible  except  in  small  portions  of  the  work.  The 
method  adopted,  therefore,  was  invariably  to  grout  with  Portland 
cement  in  the  rear  of  the  cast-iron  ring  lining  or  concrete  lining,  and 
in  the  majority  of  cases  this  application  'answered  the  purpose  of 
making  the  tunnels  perfectly  watertight.  Owing  to  the  impervious- 
ness  of  neat  cement  this  was  the  only  waterproofing  adopted 
on  the  coffer-dam  walls  of  the  Church  Street  terminal  and 
approaches. 

In  the  iron-lined  sections  of  the  tunnel  all  joints  of  the  plate 
segments  were  made  watertight  by  grommetting  the  bolts  with  flax 
and  red  lead  under  the  bolt  washers,  and  calking  the  spaces  between 
the  joints  of  the  plate  lining  with  a  thread  of  lead  wool,  followed  up 
and  supported  with  rust-joint  cement.  Throughout  the  concrete 
work,  waterproofing  was  done  by  plastering  the  internal  and  exposed 
surface  with  one  of  the  usual  types  of  waterproofing  compounds 
mixed  with  neat  Portland  cement  and  applied  with  a  trowel,  this 
method  answering  admirably  in  a  majority  of  cases.  At  the  same 
time,  in  persistent  leaks,  it  was  found  necessary  to  cut  right  back 
into  the  concrete  and  expose  the  voids  and  then  reconstruct  such 
portion  of  concrete  with  a  rich  mixture  of  cement.  As  a  general 
rule,  for  waterproofing  of  concrete  work  a  rich  mixture  of  cement  in 

*  "  Subways  and  Tunnels  of  New  York,"  by  G.  H.  Gilbert,  Lucius  I.  Wight- 
man  and  W.  L.  Saunders. 


WATERPROOFING  APPLIED  331 

the  concrete  with  thorough  and  efficient  ramming  answered  the 
purpose  and  constituted  the  only  waterproofing  used. 

Reinforced  Concrete  Standpipe.  At  Attleboro,  Mass.,  a  large 
reinforced  concrete  standpipe,  50  feet  in  diameter,  106  feet  high  from 
the  inside  of  the  bottom  to  the  top  of  the  cornice,  and  with  a  capacity 
of  1,500,000  gallons,  has  been  constructed  and  is  in  the  service  of  the 
waterworks  of  that  city.  The  walls  of  the  standpipe  are  18  inches 
at  the  bottom,  and  8  inches  at  the  top.  A  mixture  of  1  part  cement, 
2  parts  sand,  and  4  parts  broken  stone,  the  stone  varying  from  J  inch 
to  1|  inches,  was  used.  The  forms  were  constructed,  and  the  con- 
crete placed,  in  sections  of  7  feet.  When  the  walls  of  the  tank  had 
been  completed,  there  was  some  leakage  at  the  bottom  with  a  head 
of  water  of  100  feet.  The  inside  walls  were  then  thoroughly  cleaned 
and  picked  and  four  coats  of  plaster  applied.  The  first  coat  con- 
tained 2  per  cent  of  hydrated  lime  to  1  part  of  cement  and  1  part 
of  sand;  the  remaining  three  coats  were  composed  of  1  part  sand  to 
1  part  cement.  Each  coat  was  floated  until  a  hard,  dense  surface 
was  produced;  then  it  was  scratched  to  receive  the  succeeding  coat. 

On  filling  the  standpipe  after  the  four  coats  of  plaster  had  been 
applied,  the  standpipe  was  found  to  be  not  absolutely  watertight. 
The  water  was  drawn  out;  four  coats  of  a  solution  of  castile  soap 
and  one  of  alum  (Sylvester  process)  were  applied  alternately, 
and  under  a  100-foot  head,  only  a  few  leaks  then  appeared.  Prac- 
tically no  leakage  occurred  at  the  joints;  but  in  several  instances  a 
mixture  somewhat  wetter  than  usual  was  used,  with  the  result  that 
the  spading  and  ramming  served  to  drive  the  stone  to  the  bottom 
of  the  batch  being  placed,  and,  as  a  consequence,  in  these  places, 
porous  spots  occurred.  The  joints  were  obtained  by  inserting 
beveled  tonguing  pieces,  by  thoroughly  washing  the  joints  and 
covering  them  with  a  layer  of  thin  grout  before  placing  additional 
concrete. 

EXAMPLES  OF  MEMBRANE  APPLICATIONS 

East  View  Tunnel.*  Tunnels  are  usually  not  waterproofed  by  the 
membrane  system  because  of  the  difficulty  of  applying  the  membrane 
and  making  it  adhere  to  the  arch.  Therefore  the  grouting  process 
is  generally  used.  The  surface-coating  system  can  also  be  used 
successfully,  but  the  materials  must  be  carefully  chosen  and  applied. 
But  it  may  be  impossible  to  employ  either  of  these  systems  with  good 
results  because  of  the  presence  of  disintegrating  agents  in  the  soil 
*  New  York  Board  of  Water  Supply  Report  1916,  p.  135. 


332  WATERPROOFING  ENGINEERING 

or  rock  through  which  the  tunnel  passes.  Under  such  condition 
the  membrane  system  is  best  used,  and  a  case  in  point  is  the 
following:  A  1700-foot  portion  of  the  East  View  Tunnel  of  the  New 
York  Catskill  Aqueduct  was  built  in  rock  containing  iron  pyrites 
from  which  the  compound,  sulphuric  anhydride  (SO p.)  is  dissolved  by 
the  ground  water,  forming  sulphuric  acid.  This  solution,  percolating 
through  the  seams  of  the  rock,  attacked  the  limestone  aggregate  of 
the  concrete  and  also  the  cement  sufficiently  to  cause  disintegration 
in  the  concrete  lining  of  the  tunnel.  It  was  therefore  decided  to 
waterproof  this  section  by  means  of  a  3-ply  bituminous  membrane. 
The  method  pursued  in  doing  this  work  was  as  follows:  To  the 
face  of  the  partly  disintegrated  lining  was  nailed,  shingle  fashion,  No. 
28  gauge  sheet  iron.  This  acted  as  a  shedding  surface  for  the  drip 
and  a  dry-ply  upon  which  the  membrane  was  applied.  The  fabric, 
which  was  3  feet  wide  was  cut  up  into  6-foot  lengths  preparatory 
to  applying  same.  Hot  asphalt  was  mopped  on  the  sheet  iron  over 
an  area  equal  to  about  half  the  width  of  the  6-foot  strips.  Then  a 
strip  of  fabric  was  applied  (transversely  to  the  center  line  of  the 
tunnel)  and  pressed  into  the  binder.  The  other  half  of  the  strip 
was  similarly  applied.  The  second  and  third  plies  were  laid  up  like- 
wise, the  top  ply  receiving  a  final  coating  of  asphalt  on  its  entire 
surface.  Within  and  against  this  membrane  a  brick  wall,  1  foot 
thick,  was  built  completely  around  the  waterproofing. 

On  the  completion  of  this  work  the  cracks  and  crevices  in  the 
semi-disintegrated  concrete,  and  also  the  space  between  the  sheet 
iron  and  the  concrete  lining,  were  grouted.  For  this  purpose  3-inch 
pipes  were  attached  to  the  sheet  iron  and  waterproofed  around  the 
joint  before  the  brick  wall  was  built.  The  results  obtained  by  this 
method  of  waterproofing  the  tunnel  proved  entirely  satisfactory. 

The  asphalt  used  on  this  work  was  a  Mexican  refined  asphalt 
with  a  penetration  of  .55  cm.  at  77  deg.  Fahr.  The  fabric  was  a 
saturated  cotton  drill.  The  asphalt  was  heated  in  the  tunnel  in  a 
rectangular  kettle  whose  source  of  heat  was  a  battery  of  gasoline 
torch  burners  under  it.  The  gas,  contained  in  a  tank  under  pressure, 
consisted  of  about  one  part  gasoline  to  four  parts  kerosene. 

Long  Island  Railroad  Subway.  The  Atlantic  Avenue  section 
of  the  Long  Island  Railroad  *  in  Brooklyn,  N.  Y.,  is  built  of  con- 
crete (see  Fig.  119).  The  5-foot  arches,  forming  the  roof  are  sup- 
ported by  transverse  I-beams.  This  roof  was  waterproofed  in  the 
following  manner:  After  the  concrete  had  thoroughly  set  and  been 
well  dried  out  by  the  sun,  the  upper  surface  was  swabbed  over  with 
*  "  Modern  Tunnel  Practice,"  by  D.  McNeely  Stauffer. 


WATERPROOFING  APPLIED 


333 


hot,  medium-hard,  coal-tar  pitch  such  as  will  soften  at  a  temperature 
of  60  deg.  Fahr.,  and  melt  at  a  temperature  of  100  deg.  Fahr.  as  deter- 
mined by  the  cube-ih-water  method.  The  coal-tar  pitch  was  put 
on  until  it  had  a  uniform  thickness  of  not  less  than  T$  inch.  Imme- 
diately upon  the  first  coat,  and  while  it  was  still  melted,  was  laid 
1-ply  of  felt,  lapping  at  least  4  inches  on  all  cross-joints,  and  at  least 
12  inches  upon  all  longitudinal  joints.  The  felt  was  at  once  covered 
with  a  uniform  thickness  of  the  coal-tar  pitch,  and  upon  that  was  laid 
a  second  ply  of  felt  which  was  also  covered  by  not  less  than  y£  inch 
of  coal-tar  pitch.  This  membrane  extended  over  the  ends  and  down 


4.  Iron  Bands  MX  2 

(  Staggered  30  C .  to  C . 


\  Cross-section  through  Manhole.  \  Cross-section  between  Manholes. 

FIG.  119. — Cross-section  of  Atlantic  Avenue  Subway,  Brooklyn,  New  York. 

the  sides,  as  shown  in  the  cross-section.  After  the  waterproofing 
had  thoroughly  hardened,  a  1-inch  layer  of  Portland  cement  mortar 
was  laid  uniformly  over  it  with  a  trowel.  This  mortar  coat  was  laid 
in  5-foot  squares  alternately  for  the  purpose  of  providing  for  expan- 
sion and  contraction.  The  work  was  accomplished  without  difficulty 
and  with  very  good  results. 

Manhattan-Bronx  Rapid  Transit  Subway.  The  first  Rapid 
Transit  Subway  in  New  York  City  built  and  finished  between  1900- 
1903,  was  waterproofed  with  a  membrane  composed  of  two  to  eight 
plies  of  felt,  each  mopped  with  hot  asphalt,  as  laid.  On  several 
small  sections  of  the  subway,  the  felt  waterproofing  was  made  more 


334  WATERPROOFING  ENGINEERING 

effective  by  the  application  of  one  or  two  courses  of  hard-burnt 
brick  laid  in  hot  asphalt  mastic.  This  was  generally  against  the 
2-ply  membrane.  The  membranous  waterproofing  on  the  exterior 
surfaces  of  the  masonry  shell  made  it  unnecessary  to  provide  an 
extensive  system  of  drains  or  sump  pits  of  any  magnitude,  for  the 
collection  and  removal  of  water  from  the  interior  of  the  subway. 
A  few  leaks  have  developed,  mainly  due  to  enlarged  cracks,  which 
required  extensive  repairs;  but  in  general  the  waterproofing  is  good 
after  twelve  years'  service. 

The  Dual  Subway  System,  New  York  City.*  Two  types  of  water- 
proofing were  used  on  the  48  miles  of  new  two-,  three-,  and  four- 
track  subways,  viz.,  the  bituminous  membrane  and  the  brick-in- 
mastic  envelope  (the  latter,  described  under  examples  of  mastic 
applications),  the  former  on  the  roof  between  stations  and  on  side 
walls  at  stations  when  above  mean  high  or  ground  water;  the  latter 
both  at  and  between  stations  on  roof,  side  walls  and  floor  when  below 
mean  high  or  ground  water.  See  Table  XXI  for  details. 

The  fabric  used  for  the  membrane  was  7J  and  8  ounces  open- 
mesh,  jute  burlap  saturated  and  coated  with  bitumen. 

The  application  of  the  membrane  to  the  roof  is  typical  of  its 
general  use  on  the  entire  structure.  The  concrete  roof  was  swept 
clean  and  all  surface  projections  chipped  away.  The  smooth  sur- 
face, if  dry,  was  then  carefully  mopped  with  coal-tar  pitch,  using 
ordinary  wash  mops  for  this  purpose.  The  treated  fabric  was  care- 
fully unrolled  on  the  mopped  surface  (see  Fig.  120)  stretched  across 
the  entire  width  of  the  subway,  where  possible,  overlapping  1J  feet 
on  either  side.  As  it  was  unrolled  it  was  pressed  into  the  still  hot 
coal-tar  pitch  and  its  surface  mopped.  A  bond  with  the  first  coat 
of  binder  on  the  concrete  surface  was  thus  made  through  the  open- 
mesh  of  the  fabric.  A  second  ply  of  fabric  was  then  applied  so 
that  it  broke  joint  either  at  the  middle  or  at  the  one-third  point  of  the 
width  of  the  fabric.  The  surface  of  this  layer  was  similarly  mopped. 
A  third  strip  of  fabric  was  applied,  breaking  joint  over  the  second 
and  carefully  pressed  into  the  still  hot  binder.  This  process  con- 
tinued until  the  required  number  of  plies  were  laid.  The  surface  of 
the  top  ply  then  received  a  final  coating  of  binder,  leaving  it  smooth. 
The  waterproofing  membrane  that  was  thus  formed  was  allowed  to 
cool  after  which  a  4-inch  protective  coat  of  concrete  was  placed 
thereon  extending  over  the  entire  width  of  the  subway. 

*  Public  Service  Record,  published  by  the  Public  Service  Commission  for 
the  State  of  New  York,  First  District,  November,  1915,  D.  L.  Turner,  Chief 
Engineer. 


WATERPROOFING  APPLIED 


335 


At  the  time  of  its  application  the  pitch  had  a  temperature  of 
325  deg.  Fahr.  in  warm  weather  and  375  deg.  Fahr.  in  cold  weather. 
No  waterproofing  was  done  during  an  air  temperature  below 
34  deg.  Fahr. 

A  few  leaks  developed  during  construction,  but  almost  without 
exception  proved  to  be  due  to  careless  workmanship,  such  as  tares 
or  punctures  or  foot-square  holes  accidently  left  unwaterproofed 
on  the  removal  of  struts  and  shores. 


FIG.  120. — Showing  Method  of  Applying  Treated  Fabric  on  Roof  of  Subway. 
(Note  Rolls  of  Fabric,  Pitch-carrying  Pails,  and  Mop.) 


Bergen  Hill  Tunnels,  Pennsylvania  Railroad.*  In  waterproofing 
the  Bergen  Hill  tunnels  of  the  Pennsylvania  Railroad  System, 
three  general  types  of  construction  for  the  arch  were  decided  on, 
as  shown  in  Fig.  121.  The  first,  as  shown  at  A,  was  to  be  used  where 
the  tunnel  was  quite  dry.  In  this  type  the  sand  wall  was  omitted 
entirely  and  the  concrete  and  rock  packing  were  built  up  together, 
the  rock  packing  impinging  to  a  certain  extent  on  the  concrete  and  the 
concrete  squeezing  somewhat  into  the  rock  packing.  The  section 
shown  at  B  was  used  where  the  tunnels  were  damp  or  where  there 
were  slight  droppers,  not  forming  a  continuous  stream.  The  back 
lagging  of  1-inch  boards,  which  was  left  in  place  provided  a  practically 
smooth  outer  surface  on  the  concrete  arch  and  allowed  the  concrete 
and  rock  packing  to  be  built  almost  simultaneously.  It  was  con- 

*  Transactions  of  the  American  Society  of  Civil  Engineers,  Vol.  68,  p;  142. 


336 


WATERPROOFING  ENGINEERING 


sidered  that  the  free  drainage  through  the  rock  packing,  the  surface 
of  the  boards  and  the  smooth  outer  surface  of  the  concrete  in  the 
arch  would  allow  the  comparatively  small  quantity  of  water  in  these 
parts  of  the  tunnel  to  find  its  way  to  the  sides,  thence  to  the  ditches 
at  the  bottom,  rather  than  percolate  through  the  concrete.  This 
proved  to  be  very  generally  the  case,  as  is  shown  by  the  dry  condition 
of  the  tunnel  as  built.  The  back  lagging  was  used  over  the  arch, 


Method  of 

Method  of  making  laPPin*  Mats 

Three-ply  MaU 

DETAILS  OF  WATERPROOFING 

One  layer  of  felt  with  4"  overlap  to 
be  nailed  to  lagging  of  inch  boards, 
using  tin  washers  on  nails  over  the 
whole  of  the  intrados  of  the  arch  be- 
fore starting  any  concrete  or  placing 
any  of  the  permanent  felt  and  pitch 
waterproofing.  The  waterproofing 
over  the  arch  can  be  laid  in  mats  of 
three  thicknesses  of  felt  properly 
joined  together  with  pitch  made  as 

shown  diagrammatically  at  x. 
Each  of  these  mats  of  three-ply  felt 

will  be  overlapped  half  the  width  of 

the  mat,  as  shown  diagrammatically 

at  y. 

FIG.  121. — Various  Types  of  Arch  Waterproofing  Used  on  Bergen  Hill  Tunnels. 


both  where  the  sand  wall  was  built  and  where  it  was  omitted,  as  well 
as  being  placed  over  the  waterproofing  of  the  arch  as  an  armor 
course  where  waterproofing  was  required.  Where  the  sand  walls 
were  built  and  waterproofed,  and  where  the  waterproofing  was  not 
carried  over  the  arch,  the  waterproofing  was  turned  in  at  the  top, 
as  shown  at  C. 

The  third  method  provided  for  waterproofing  the  whole  of  the 
arch.  This  was  the  same  as  B  except  for  the  addition  of  the  water- 
proofing inside  the  back  lagging.  In  placing  this  waterproofing, 
the  felt  was  cut  in  strips  about  11  feet  long  (about  1  foot  longer  than 
the  length  of  a  section  of  arch)  and  six  thicknesses  were  cemented 


WATERPROOFING  APPLIED  337 

together  with  hot  coal-tar  pitch.  These  mats  were  then  laid,  shingle- 
fashion,  as  shown  at  D,  up  the  sides  of  the  arch  until  a  space  about 
5  feet  wide  remained  at  the  crown;  shorter  mats  were  then  brought 
out  over  this,  laying  them  perpendicular  to  the  axis  of  the  tunnel. 
Care  was  taken  in  making  all  laps,  irrespective  of  the  direction  in 
which  the  arch  was  built,  so  that  they  would  lay  with  the  grade, 
that  is,  so  that  the  water  would  tend  to  flow  over  the  edges  of  the 
laps  rather  than  against  them. 

The  method  of  waterproofing  that  part  of  the  timbered  section 
which  was  very  wet  is  shown  at  F.  A  lagging  of  1-inch  boards 
was  nailed  up  the  sides  sjid  to  the  soffit  of  the  segmental  timbering, 
all  the  spaces  outside  of  this  lagging  being  carefully  filled  with  rock 
packing.  Before  starting  any  concrete  work  a  single  thickness  of 
waterproofing  felt  was  nailed  to  the  inner  side  of  the  lagging,  which 
not  only  served  to  protect  the  finished  surfaces  of  the  concrete 
from  the  water  which  fell  copiously  from  the  roof,  but  also  provided 
a  comparatively  dry  surface  to  which  the  regular  6-ply  waterproofing 
could  be  cemented  with  pitch  and  held  in  position  while  the  concrete 
was  placed  against  it 

Boston  Tunnels.*  A  section  of  the  Boston,  Mass.,  subway  con- 
sists of  two  tunnels  underneath  the  Fort  Point  Channel.  These  tun- 
nels are  built  with  an  outer  shell  9  inches  thick  made  of  Southern 
long-leaf  pine-wood  segments  and  an  inside  concrete  shell  2  feet  thick 
(minimum)  with  steel  reinforcement.  These  tunnels  are  water- 
proofed by  the  application  of  a  bituminous  membrane  to  the  interior 
of  the  wooden  shell  before  placing  the  interior  concrete  lining  (see 
Fig.  122).  This  membrane  consists  of  layers  of  treated  cotton  fabric 
mopped  with  hot  asphalt.  Two  layers  are  put  on 'the  invert  and  three 
on  the  sides  and  arch.  In  applying  the  waterproofing  to  the  sides 
and  arch,  the  first  layer  of  cloth  was  mopped  on  one  side  with  asphalt 
and  then  nailed  to  the  wooden  lining  with  roofing  nails,  the  mopped 
side  being  against  the  wood.  The  second  and  third  layers  were 
then  stuck  on  with  successive  moppings  of  hot  asphalt.  The  result 
after  three  years'  service  is  entirely  satisfactory. 

Waterproofing  Railroad  Viaducts.  The  following  unique  method 
of  waterproofing  the  Martins'  Creek  and  Tunkhannock  Viaducts 
on  the  new  line  which  the  Lackawanna  Railroad  has  recently  built 
west  of  Scranton,  Penna.,  is  described  as  follows  by  Mr.  G.  J.  Ray, 
Chief  Engineer. f  "The  structures  referred  to  were  treated  alike, 
the  same  waterproofing  materials  being  used  in  each  case.  The 

*  Engineering  Record,  August  21,  1915. 

t  Engineering  News,  Vol.  75.  March  2,  1916. 


338 


WATERPROOFING  ENGINEERING 


floor  system  over  each  main  arch  is  divided  into  three  parts  by  four 
transverse  expansion  joints — two  adjacent  to  each  pier  and  one  at 
each  of  the  quarter  points  of  the  span.  The  floor  is  drained  by 
downspouts  through  all  spandrel  walls,  excepting  those  at  the 
two  intermediate  expansion  joints,  and  the  drainage  is  discharged 
into  the  openings  between  the  two  ribs  of  the  main  arch.  The 
drainage  is  prevented  from  flowing  over  the  expansion  joints  by 
dikes  built  across  the  floor  (enlarged  details  are  shown  in  Fig.  123). 
"  The  waterproofing  proper  was  done  by  using  three  plies  of 
saturated  cotton  fabric  laid  in  hot  asphalt.  The  concrete  was  first 


FIG.    122. — Waterproofing  is   Placed   against  Wooden   Lining  and  Outside   of 
Concrete  on  Shield-driven  Tunnel,  Boston,  Mass. 


mopped  with  the  hot  asphalt.  The  three  layers  of  cloth  were  then 
laid  in  the  usual  manner,  each  layer  being  mopped  before  the  applica- 
tion of  the  succeeding  layer.  This  waterproofing  was  carried  up 
the  sides  of  the  parapet  wall  to  the  top  of  the  ties  and  directly  across 
all  expansion  joints,  so  that  the  waterproofing  was  in  reality  continu- 
ous from  one  end  of  the  bridge  to  the  other.  At  the  expansion  joints 
one  additional  layer  of  the  saturated  fabric  was  laid  across  and 
folded  in  the  expansion  joint  beneath  a  copper  flashing,  similarly 
laid,  over  which  the  three  layers  of  waterproofing  were  placed.  A 
fold  was  provided  in  the  waterproofing  at  the  joints  to  provide 
for  expansion  and  the  entire  joint  filled  with  the  hot  asphalt. 


WATERPROOFING  APPLIED 


339 


"  As  a  protection  to  the  waterproofing,  asphalt-mastic  mixed  with 
washed  torpedo  gravel,  was  applied  hot  in  two  f-inch  layers  over  the 
entire  area  of  the  waterproofing.  In  order  to  avoid  injury  to  the 
waterproofing  by  the  hot  mastic,  1  ply  of  asbestos  felt  was  first  laid 


LONGITUDINAL 

SECTION   OF 
VIADUCT   SHOWING 
POSITION  OF  DIKE 
JOINTS  OVER  PIER 


3-Ply  Cloth 
16-oz  Copper  "A" 
1-Ply  Cloth 


SECTION  A-A 


SECTION  B-B 


FIG.  123.— Dike  Form  of  Expansion  Joint,  and  Details  of  Waterproofing  on  the 
Martin's  Creek  Viaduct. 

over  the  entire  area  of  the  membrane.  An  opening  was  left  in  the 
mastic  directly  over  the  center  of  each  expansion  joint  and  filled  with 
the  hot  asphalt.  The  asphalt-mastic  was  used  for  protection  in  prefer- 
ence to  brick  or  concrete,  since  our  experience  elsewhere  with  this 
mastic,  under  ballast,  indicates  that  it  does  not  crack  and  in  reality 


340  WATERPROOFING  ENGINEERING 

forms  a  secondary  waterproofing  surface  on  which  the  drainage 
readily  passes  to  the  downspouts." 

Terrace,  United  States  Capitol.  The  pavement  over  the  terrace 
chambers  of  the  United  States  Capitol  at  Washington,  D.  C.,  has 
been  made  watertight  by  the  membrane  system  after  many  failures 
by  other  systems.* 

Many  methods  of  waterproofing  have  been  tried  on  this  great 
expanse  (about  200,000  square  feet)  of  walk,  to  wit:  felt  and  coal- 
tar  pitch,  asphalt  and  burlap,  sheet  asphalt,  etc.  In  1906  a  sheet- 
lead  pan  was  placed  under  one  section.  The  sheet  lead  was  bedded 
in  cement  mortar  on  the  base  slab  and  was  covered  with  a  3-inch 
reinforced  concrete  slab  and  a  1-inch  wearing  surface.  But  even 
this  construction  was  of  no  avail,  partly  because  of  the  extreme 
expansion  movement,  partly  because  of  unskilled  burning  of  the  sheet 
joints  and  partly  because  of  the  inherent  difficulties  of  flashing 
around  the  vault  light  frames.  The  sheet  lead  on  being  uncovered 
was  found  to  be  considerably  pitted. 

The  expansion  and  contraction  movements  of  the  terrace  struc- 
ture are  excessive,  owing  to  wide  variations  in  temperature  and 
extreme  exposure.'  Insufficient  provision  was  made  for  inevitable 
expansion  movement,  and  to  this  defect  can  be  finally  traced  the 
repeated  failures  to  keep  the  terrace  chambers  watertight.  Final 
success  was  largely  due  to  recognizing  expansion  difficulties  and  pro- 
viding for  such  movement  by  watertight,  sealed  expansion  joints. 

Specifications  were  issued  for  this  work  in  1914.  The  notable 
features  of  these  specifications  consisted  (1)  in  securing  a  bituminous 
compound  having  maximum  adhesiveness  and  cohesion,  (2)  in  using 
small  (1  square  yard)  freshly  saturated  cotton  fabric  sheets,  with 
wide  laps,  mopped  into  place  and  covered  with  protective  masonry, 
(3)  in  the  free  use  of  special  expansion  and  flashing  joints. 

The  material  over  the  terraces  was  removed  down  to  the  con- 
crete slab  over  the  floor  arches  which  disclosed  numerous  fractures 
in  the  base  slab.  Each  crack,  treated  as  an  expansion  joint,  was 
cleaned  out,  heated  with  a  gasoline  torch,  partly  filled  with  a  special 
asphalt  compound  and  tooled  with  a  hot  iron  as  shown  in  Fig.  124. 
The  slab  was  also  cut  for  expansion  joints,  as  shown  in  Fig.  125. 

After  the  expansion  joints  were  filled,  the  pavements  were 
brought  up  to  subgrade  by  a  filling  of  1  :  3  :  6  concrete.  Upon  the 
leveled  subgrade  was  laid  single  sheets  of  impregnated  cotton  drill. 
The  sheets  were  1  yard  square  and  were  laid  with  2-inch  laps.  A  small 
area  of  subgrade  was  cleaned  and  mopped  with  hot  compound  just 
*  Engineering  News,  Vol.  76,  No.  14,  October  5,  1916. 


WATERPROOFING  APPLIED 


341 


previous  to  laying  each  sheet.  The  laps  were  made  tight  by  follow- 
ing with  a  hot  smoothing  iron.  Upon  the  membrane  thus  made  there 
was  laid,  as  armor  for  the  waterproofing  and  as  a  wearing  surface, 
a  granolithic  pavement  (1:1:2  mixture  with  i  to  f  inch  washed 
bluestone  chips),  marked  off  in  squares.  These  squares  were  sepa- 
rated by  expansion  joints  continuous  with  the  expansion  joints  in 
the  subbase,  as  shown  in  Fig.  125,  also  along  the  balustrades,  vault 
lights,  and  at  every  point  where  flashing  would  ordinarily  have  been 
employed. 

In  waterproofing  the  expansion  joints,  the  cut  in  the  bottom  slab 
was  heated,  painted  and  partly  filled  with  the  asphaltic  compound. 
Then  the  membrane  was  brought  down  into  the  opening  and  the  joint 
pointed  with  mortar.  The  joint  was  covered  with  a  patch  strip 


FIG.   124. — Slab   Cracks   Made  into   Expansion  Joints  in  Waterproofing  the 
Capitol  Terraces,  Washington,  D.  C. 

(see  detail  X  on  Fig.  125),  completing  the  lower  half.  When  the 
granolithic  paving  was  laid,  wood  strips,  tapered  f  to  J  inch,  were 
inserted  as  joint  forms.  When  the  concrete  had  set,  the  wood  was 
pulled  out,  the  opening  heated  and  partly  filled  with  the  compound. 
The  remaining  space  was  pointed  with  mortar.  In  this  way  a  covered 
and  sealed  reservoir  was  created  at, each  expansion  joint.  As  the 
structure  contracts  and  expands,  the  mortar  plug  is  drawn  down  or 
forced  out,  the  seal  being  preserved.  After  one  summer's  use  the 
joints  were  found  all  closed  nearly  tight,  demonstrating  that  by  use 
of  a  thin  plastic  membrane  underlying  the  wearing  surface  the  latter 
could  be  kept  from  spalling  or  cracking. 

Manhattan  and  Brooklyn  Railroad  Viaducts.  In  building  rail- 
road viaducts  through  city  streets,  where  space  is  usually  very 
valuable  and  scarce,  and  economy  of  operation  the  governing  factor 
in  the  type  of  structure  required,  it  has  become  the  practice  to  con- 
struct the  stations  underneath  the  track  level,  instead  of  projecting 


342 


WATERPROOFING  ENGINEERING 


WATERPROOFING  APPLIED 


343 


them  into  the  side  streets  on  a  level  with  the  tracks.  This  new 
practice  necessitates  the  portion  of  track  floor  or  road  bed  directly 
over  the  station  mezzanine  to  be  perfectly  watertight.  To  best 
accomplish  this  the  steel  work  at  these  locations  of  the  elevated 


No.18  Galranized  wire  lath  1^'mesh      £ 
1' 6" wide  across  brackets. 


,. 

_  •'.    ':.       ..-^..v...'  ;/-.;-;:-v:-J-.,  .    ...    ..::-.-.....:•  .--.      ^JU  ..-.-  :' 


—T-  •  NN6.18  Galvanized  wire  lath  1J£  m€ 

/  f         Waterproofing  shall  be  flashed  3'0"wide,  entire  length. 

V  <  over  brackets  and  against  girders 
v  to  form  a  perfect  seal. 

CROSS  SECTION  "A-B" 


Waterproofing 


ired 


PLAN  SECTION  AT  BASE  OF  RAIL 


CROSS  SECTION  OF  CONCRETE  DECK 

ON  THROUGH  SPANS 

SHOWING  METHOD  OF  WATERPROOFING  A  PLACING. 
OF  PROTECTIVE  CONCRETE 

METHOD   USED    BY 

NEW  VORK   MUNICIPAL  RAILWAY  CORP. 

ON    BROADWAY  ADDITIONAL  TRACKS 

BROOKLYN,  NEW  YORK 


FIG.  126. — Method  of  Waterproofing  Concrete  Decks  on  Through  Spans,  Used 
by  the  New  York  Municipal  Railway  Corporation. 

structure  should  be  designed  free  of  bays  and  unnecessary  connections, 
and  should  also  be  encased  in  concrete.  This  concrete,  forming  the 
roadbed,  may  be  constructed  in  sections  as  shown  in  Fig.  128, 
which  is  not  advisable,  or  in  monolithic  form  as  shown  in  Figs.  126 


344 


WATERPROOFING  ENGINEERING 


and  127.  A  design  very  successful  in  this  respect  is  used  by  the 
New  York  Municipal  Railway  Corporation  of  Brooklyn,  N.  Y.,  on 
several  of  its  elevated  lines  (see  Fig.  126). 

Waterproofing  on  the  concrete  roadbeds  over  the  mezzanine  floors 
of  these  stations  consists  of  a  2-ply  membrane  composed  of  treated 
cotton  fabric  and  asphalt  binder,  applied  over  the  concrete  and  lapped 
on  to  the  steel  girders.  Sometimes  the  ends  of  the  membrane  were 


Surface  of  Concrete: 
At  Stiffener  Angles 
Between  Stiffener  Angles 


4  Lap  of  Membrane 
Construction  Joint 
Reinforcing  Rods 
Stiffener  Angle 


ISOMETRIC  VIEW  SHOWING   DETAIL  "A" 
OF  CONCRETE  AT  STIFFENER   ANGLE 


Waterproofing 
Membrane 


FIG.  127. — Section  of  Girder  of  Railroad  Viaduct  Showing  Membrane  Water- 
proofing, Protective  Concrete,  and  Drip  Channel. 

put  into  V-joints  between  the  concrete  and  steel  webs;  these  joints 
were  then  filled  with  an  adhesive,  elastic,  bituminous  compound. 
Over  this  membrane  was  placed  a  minimum  of  4  inches  of  protective 
concrete.  This  concrete  is  brought  up  the  sides  of  the  girders  to  the 
top  flange  in  monolithic  form.  This  trough-type  construction  of 
track  floors  has  proved  very  succeesful.  A  design  even  more  efficient 
than  the  above  one,  from  the  waterproofing  standpoint,  is  shown 
in  Fig.  127.  In  this  design  a  dripping  surface  is  provided  by  the 


WATERPROOFING  APPLIED 


345 


substitution  of  a  steel  channel  for  one  of  the  cover  plates  of  the  steel 
girder.  Fig.  128  shows  the  design  of  a  steel  and  concrete  roadbed 
on  a  few  railroad  viaducts  in  New  York  City.  The  waterproofing 
details,  one  of  which  is  shown  in  Fig.  129,  were  not  entirely 
adequate. 

In  connection  with  the  design  and  construction  of  watertight  steel 
and  concrete  road  beds  of  railroad  viaducts  it  is  proper  to  point  out 
to  the  engineer  whose  duty  it  is  to  design  the  waterproofing  for  such 
locations  that  he  would  do  well  to  carefully  study  the  details  connected 
therewith.  He  knows,  for  instance,  that  the  structure  is  subject  to 


3x2   Sleepers  Platform 


2   Board 
Waterproofing 
^"Expansion  Bolta 
2"x  12  "Lumber 


a  Rods  1  6  Ctrs. 


Mezzanine  Floor , 


3'  Finish^ 


a  Rods  6  Ctrs. 


y>"a  Rods  i 6' Ctrs. 


FIG.  128. — Typical  Construction ,  of  Mezzanine  Roof  on  Elevated  Railroad 
Structures  in  New  York  City,  Showing  Location  and  Protection  of  Mem- 
brane Waterproofing. 


severe  vibration;  he  should  know,  also,  that  a  comparatively  thin 
layer  of  concrete  or  mortar  is  almost  useless  for  the  protection  of 
waterproofing  under  such  conditions.  He  probably  knows  that  only 
the  membrane  or  perhaps  the  surface-coating  types  of  waterproofing 
are  serviceable  for  such  a  structure,  but  he  should  know  also  that 
joints  between  steel  and  concrete  can  remain  watertight  only  so  long 
as  the  joint  filler  remains  plastic,  though  even  this  is  doubtful,  in  view 
of  the  difficulties  experienced  in  the  design  lastly  referred  to. 

Still  another  feature  peculiar  to  such  structures,  as  shown  in  Fig. 
128,  would  be  revealed  by  a  careful  study  of  details  and  that  is,  that 


346  WATERPROOFING  ENGINEERING 

openings,  large  and  small,  crevices  and  pockets  in  the  joints  and 
connections  of  the  steel  members  which  cannot  be  filled  or  covered 
with  the  bed  concrete,  require  calking.  Or  else  the  waterproofing 
must  be  carried  up  the  sides  of  the  steel  work,  suitably  protected 
and  high  enough  to  effectually  prevent  the  percolation  of  water 
through  the  joints  and  connections.  Unless  either  of  these  things  is 
done  no  amount  or  quality  of  waterproofing  of  the  roadbed  proper 
will  make  the  structure  watertight. 

The  following  is  a  case  in  point  that  has  been  brought  to  the 
attention  of  the  author  and  well  illustrates  the  need  for  careful 
study  of  waterproofing  details.  Fig.  128  is  a  cross-section  through  a 
steel  viaduct  where  a  mezzanine  floor,  roadbed,  and  elevated  plat- 
form are  shown. 

The  purpose  of  the  concrete  roadbed  is  to  form  a  solid  roof 
protection  for  the  structure  underneath,  and  the  concrete  of  the  ele- 
vated platform  serves  a  like  purpose.  Now,  it  is  rightly  assumed  by 
the  engineer  that  the  concrete  may  crack  in  the  course  of  time  and 
allow  water  to  seep  through  to  the  mezzanine  floor  below.  To 
obviate  this  danger  he  specifies  a  3-ply  membrane  to  be  laid  on  the 
concrete,  and  covered  with  a  4-inch  protective  coat  of  concrete. 
Realizing  that  the  protective  concrete  cannot  make  a  watertight 
joint  with  the  webs  of  the  girders  or  beams,  the  concrete  covering 
is  designed  so  as  to  leave  a  V-shaped  joint  between  it  and  the  steel, 
as  shown  in  Fig.  129. 

Even  when  a  good  elastic  compound  is  used  as  a  filler,  the  mate- 
rial cannot  last  for  more  than  a  few  years  and  retain  the  properties 
requisite  for  waterproofing  under  this  condition.  Hence,  sole  reliance 
upon  such  a  material  to  always  effectively  seal  the  joint,  is  unwar- 
ranted. Still  more  so  is  the  use  of  a  high  melting-point  bitumen,  such 
as  a  hard  coal-tar  pitch  or  asphalt,  because  they  become  extremely 
brittle  materials  at  temperatures  but  little  below  the  ordinary.  Al- 
most the  first  train  that  would  cross  the  viaduct  during  cold  weather 
would  cause  the  pitch  in  the  V-joints  to  crack  and  break  away  from 
one  of  the  two  surfaces,  after  which  it  would  be  useless  as  a  means 
of  preventing  water  from  seeping  through  the  joint  or  getting  around 
and  under  the  membrane.  It  is  a  fact  that  plastic  joint  fillers  have 
actually  failed  in  this  regard;  that  is,  the  joints  between  the  steel 
and  the  filler  opened  and  nullified  the  value  of  the  rest  of  the  water- 
proofing. It  is  equally  a  fact  that  this  result  is  inevitable,  because 
of  the  varying  rates  of  vibration  between  the  structural  materials 
when  a  train  passes  over  the  structure  due  to  the  relatively  different 
inertia  of  the  steel  and  the  concrete. 


WATERPROOFING  APPLIED 


347 


348 


WATERPROOFING  ENGINEERING 


An  arrangement  that  would  prove  more  efficient,  though  somewhat 
costlier,  is  shown  at  A  in  Fig.  130.  In  this  form  of  construction,  the 
effective  waterproofing  of  the  structure,  or  rather,  the  making  of 
watertight  joints  is  practically  independent  of  the  joint  filler.  This 


-3-Ply  Membrane 


FLANGE  ANGLE  V- JOINTS 


3-Ply  Membrane 


Mop  concrete 
(  under  flashing 


FLASHING   V-JOINT 
FIG.  130. — Improved  Types  of  V-joints  for  Elevated  Structures. 

form  of  construction  may  also  be  modified  so  as  to  have  the  angle  iron 
act  as  a  flashing  instead  of  a  joint,  as  shown  at  B  in  Fig.  130.  A 
strip  of  thin  sheet  lead  between  the  angle  and  web  is  recommended. 
An  arrangement,  whereby  the  angle  iron  is  eliminated  and  a  copper 
flashing  substituted,  is  shown  at  C,  Fig.  130.  This  desien  is 


WATERPROOFING  APPLIED 


349 


efficient  than  the  above  two,  because  if  the  joint  filler  should  fail  to 
act,  it  would  still  be  almost  impossible  for  water  to  get  around  the 
flashing  and  seep  through  the  joint.  This  design,  however,  is  costlier 
and  requires  great  care  when  applying  and  soldering  together  the 
sections  of  the  flashing  and  in  the  selection  of  the  metal.  In  design- 
ing the  protective  concrete,  it  is  often  necessary  and  always  advis- 
able to  reinforce  it  with  some  form  of  wire  mesh  of  which  the  trans- 
verse ends  should  be  left  projecting  somewhat  into  the  joint  filler. 
Fig.  131  shows  a  way  to  utilize  the  protective  concrete  so  as  to  secure 
watertightness  in  the  track  floor.  Other  methods  will  undoubtedly 


mm. 


FIG.  131. — Waterproofing  Details  around  Ferrules  at  Drains,  also  Showing 
Increased  Utility  of  Protective  Concrete  over  Membrane  on  Mezzanine 
Track  Floor  of  Elevated  Structure. 

suggest  themselves  upon  careful  consideration  of  the  conditions  at 
hand.  The  purpose  of  this  digression  is  merely  to  call  attention  to 
the  need  of  studying  waterproofing  details  and  carefully  selecting 
the  materials. 

Perhaps  the  citation  of  another  glaring  instance  of  an  ineffectual 
design  and  application  of  waterproofing  will  impress  the  architect, 
engineer  and  contractor  with  the  serious  consequences  following  a 
disregard  of  the  need  to  study  details  and  understand  the  selection 
of  waterproofing  materials. 

A  very  important  station  on  one  of  the  Brooklyn  (New  York) 
Elevated  lines  consists  of  a  double-deck  concrete  structure  built 
partly  below  ground  surface.  The  ceiling  above  the  platform  of 
the  lower  deck  is  raised  and  forms  the  train  platform  of  the  upper 


350 


WATERPROOFING  ENGINEERING 


deck.  The  track  floors  between  the  platforms  of  the  upper  deck  are 
waterproofed  with  a  6-ply  membrane  made  of  treated  jute  fabric 
and  coal-tar  pitch  having  a  melting-point  of  120  deg.  Fahr.  by  the 
cube-in- water  method.  This  membrane  terminates  directly  over 
the  webs  of  the  platform  girders  as  shown  at  A,  Fig.  132.  These 
girders  support  concrete  walls  which,  in  turn,  support  the  platform 
of  the  upper  deck.  The  first  summer  after  the  station  was  com- 
pleted considerable  quantities  of  the  binder  exuded  through  and  all 
along  the  construction  joints  between  this  concrete  and  the  top  flange 
of  these  girders. 


u^=^  ^ 

' 

•    10'  ft" 

^-^aHJ 

Platform 
Upper  Level 

T 
1  . 

'  Protective  concrete 
placed  Jon  waterproofing 
before  track  was  placed 


FIG.  132. — Cross-section  of  Station  Platform  and  Track  Floor,  Showing  Scheme 
of  Waterproofing  Proposed  and  Used  on  a  Sub-level  Railroad  Structure 
in  New  York  City. 

The  resulting  defacement  of  the  structure  and  injury  to  the  water- 
proofing was,  however,  not  due  to  a  poor  grade  of  material  nor  bad 
workmanship  in  the  application  of  the  waterproofing,  but  was  entirely 
due  to  faulty  design,  as  is  evident  from  the  figure,  and  the  neglect 
to  specify  a  binder  of  an  asphaltic  nature  or  a  coal-tar  pitch  of  at 
least  30  deg.  Fahr.  higher  melting-point.  That  this  precaution  should 
have  been  taken  follows  from  the  fact  that  the  station  has  a  super- 
structure which  is  exposed  to  the  elements  and  hence  the  concrete 
may  easily  acquire  a  temperature  above  100  deg.  Fahr.  in  the  sum- 
mer time. 


WATERPROOFING   APPLIED  351 

Another  point  worth  mentioning  is  that  the  purpose  of  the  water- 
proofing membrane  in  this  particular  structure  is  such  as  hardly 
requires  more  than  three  plies,  and  the  way  this  should  have  been 
applied  is  shown  at  B,  in  Fig.  132,  which  is  self-explanatory. 

Waterproofing  Reinforced  Concrete  Standpipes.  In  the  design  of 
reinforced  concrete  standpipes,  engineers  have  hitherto  met  with 
little  success  in  obtaining  watertight  tanks  for  several  reasons: 

1.  Because    of    insufficient    attention    to    proper    grading    and 
proportioning  of  concrete  aggregates. 

2.  Imperfect  design  of  expansion  joints  (see  Fig.  45  for  a  suc- 
cessful type  of  expansion  joint). 

3.  Laxity  in  supervision  and  workmanship  during  construction. 

4.  Insufficient  attention  to  details. 

Nearly  all  standpipes  are  so  conditioned  during  their  use  that  the 
concrete,  especially  the  lower  portion  of  the  standpipe,  is  subjected 
to  varying  stresses  consequent  upon  changing  heads  of  water.  During 
this  action  the  stresses  in  the  reinforcement  likewise  vary,  hindering 
the  silting  up  of  minute  cracks  that  may  have  formed  and  which  after 
a  freezing  season  may  become  dangerously  large. 

Hence,  it  may  be  concluded  that  any  structure  subject  to  so 
many  different  kinds  of  stresses  as  is  a  concrete  standpipe  is  best 
made  waterproof  by  the  application  of  a  bituminous  membrane  of 
from  two  to  four  plies  of  fabric  or  cotton  drill  applied  on  the  inside, 
and  covered  with  a  coat  of  mortar  J  to  1  inch  thick.  This  method 
obviates  the  need  of  extraordinary  precautions  in  grading  and  super- 
vision, and  it  will  also  be  found  that  the  cost  is  no  greater  and  results 
more  certain  than  when  using  either  the  integral  or  self-densified 
system  of  waterproofing.  This  method  has  been  followed  in  several 
instances  with  success. 

Waterproofing  Floor  of  Pneumatic  Caisson.  To  aid  the  engineer 
in  his  judgment  and  to  avoid  delay  in  the  execution  of  the  waterproof- 
ing work  in  hand,  he  will  do  well  to  resort  to  some  practical  field 
tests  for  the  determination  of  the  working  properties  of  a  material 
or  method  not  heretofore  used  or  not  used  under  extraordinary 
conditions.  A  case  in  point  is  the  following:  Specification  require- 
ments for  waterproofing  the  floor  of  a  pneumatic  caisson  used  in 
connection  with  the  construction  of  two  tunnels  under  the  East 
River  connecting  the  William  and  Clark  Streets  subway  between 
the  boroughs  of  Manhattan  and  Brooklyn  (see  Fig.  Ill)  called  for  a 
"  soft  pitch  which  will  soften  at  32  deg.  Fahr.  and  melt  at  about 
60  deg.  Fahr.  so  that  it  can  be  spread  without  heating."  Its  use  was 
intended  for  waterproofing  under  compressed  air  where  the  fumes 


352  WATERPROOFING  ENGINEERING 

of  hot  melted  coal-tar  pitch  would  be  unbearable  to  the  workmen  and 
give  rise  to  fire  risks.  But  such  a  low  melting-point  coal-tar  pitch 
is  not  a  commonly  used  waterproofing  material  and  must  be  made  up 
specially,  hence  delay  and  increased  cost  may  result. 

The  compressed  air  chamber  was  under  about  20  pounds  pres- 
sure, and  had  an  air  temperature  of  about  75  deg.  Fahr.  After 
completion,  the  concrete  floor  and  the  waterproofing  underneath 
would  have  a  temperature  about  20  deg.  below  this,  with  the  result 
that  the  low  melting-point  pitch  would  exude  from  cracks  or  would 
tend  to  flow  toward  any  hollow  or  other  depression  in  the  concrete 
and  perhaps  nullify  the  purpose  of  the  waterproofing.  To  avoid 
this  condition  and  still  use  coal-tar  pitch,  for  pitch  was  the  only 
material  allowed  under  the  specifications,  a  straight-run  coal-tar 
pitch  having  a  melting-point  of  about  120  deg.  Fahr.  by  the  cube- 
in-water  method,  was  first  tried;  that  is,  it  was  heated  to  about 
325  deg.  Fahr.  or  over,  poured  in  small  buckets  and  lowered  into 
the  caisson.  But  coal-tar  pitch,  when  heated  to  a  temperature 
of  about  325  deg.  Fahr.  as  was  done  in  this  instance,  fumes  offensively. 
A  test,  by  the  author,  to  determine  the  temperature  at  which  fumes 
commence  to  be  given  off  by  the  molten  pitch  showed  that  hardly 
any  was  given  off  until  a  temperature  of  about  225  deg.  Fahr.  was 
reached.  Hence  all  that  was  required  was  not  to  heat  the  coal- 
tar  pitch  beyond  this  point  and  a  regular,  stock  material  could  be 
used.  After  a  single  trial  it  was  used  in  this  manner  very  success- 
fully. However,  in  the  case  of  another  caisson  under  about  40  pounds 
pressure  per  square  inch,  the  soft  grade  of  pitch  called  for  in  the  speci- 
fication was  used  (necessitated  by  the  greater  fire  risk)  and  the  work 
well  accomplished. 

Waterproofing  Steel  Swimming  Tank.*  A  swimming  tank, 
30  by  60  feet  in  plan,  and  from  4  feet  to  8J  feet  deep,  situated  between 
the  10th  and  llth  floors  of  the  Union  League  Club  House  in  Chicago, 
was  waterproofed  by  the  application  of  a  sheet-lead  membrane  and 
a  felt  membrane  against  the  lead.  Before  applying  the  sheet-lead 
membrane  the  rivet  heads  on  the  inside  of  the  girders  forming  the 
sides  of  the  tank  were  flattened  to  J  inch.  Over  the  entire  area 
1J  inches  of  cement  mortar  was  put  on  with  a  cement  gun.  Upon 
this  mortar  coat  the  sheet  lead,  weighing  4  pounds  per  square  foot 
(about  Te  inch  thick),  was  placed  and  tacked  to  wooden  strips  set 
in  the  mortar.  All  the  joints  were  soldered.  Then  the  felt  membrane 
was  applied,  being  bonded  with  coal-tar  pitch,  and  covered  with  4 
inches  of  cement  mortar  also  put  on  with  the  cement  gun.  The  entire 
*  Engineering  Record,  Vol.  75,  No.  3,  January  20,  1917,  p.  107. 


WATERPROOFING  APPLIED  353 

inside  was  then  lined  with  ceramic  tile  J  inch  thick,  set  in  cement 
mortar. 

The  above  scheme,  suggested  by  the  contractor,  and  which 
proved  very  satisfactory,  was  substituted  for  the  original  specifica- 
tion calling  for  membrane  waterproofing  with  calking  and  welding 
of  joints  to  make  the  steel  watertight. 

EXAMPLES  OF  MASTIC  APPLICATIONS 

Waterproofing  Roadbed  Over  Mezzanine.  Some  of  the  track 
floors  over  the  station  mezzanines  on  an  elevated  railroad  in  Brooklyn, 
New  York,  consist  of  a  framework  of  steel  beams  and  girders  with 
concrete  slabs  in  the  open  spaces,  forming  a  series  of  bays  (similar 
to  Figs.  128  and  129).  These  bays  are  waterproofed  with  a  mastic 
sheet  approximately  2  inches  in  thickness  placed  directly  on  the 
concrete.  Each  bay  is  drained  by  a  pipe  to  the  adjacent  one  until 
the  water  reaches  an  end  but  central  bay,  from  which  it  passes  into 
a  copper  gutter.  The  drains  are  3-inch  wrought-iron  pipes,  12  inches 
long,  passing  through  the  steel  webs  to  which  they  are  fastened  by 
means  of  ferrules  and  made  to  adhere  to  the  mastic. 

Before  the  mastic  was  applied  to  the  concrete  slabs,  2-inch  strips 
of  the  steel  webs  were  mopped  at  the  required  elevation  with  asphalt 
to  secure  a  good  bond  between  both.  The  mastic  consisted  of 
approximately  12  per  cent  asphalt,  14  per  cent  sand,  22  per  cent 
grit,  and  52  per  cent  limestone  dust. 

Though  the  mastic  was  well  made  and  applied,  and  was  in  good 
condition  more  than  a  year  after  application,  it  gave  very  poor 
waterproofing  results.  This  was  directly  traceable  to  the  poor  bond 
between  the  steel  webs  and  the  mastic,  being  broken  by  the  severe 
vibration  in  the  structure  and  especially  the  non-synchronous 
vibration  between  the  concrete  slabs  and  the  steel  framework. 

The  Dual  Subway  of  New  York  City.  In  waterproofing  the  new 
subways  in  New  York  City  two  systems  were  used.  The  membrane 
(described  under  examples  of  membrane  applications)  and  the 
brick-in-mastic  envelope  (described  below).  The  latter  method  was 
used  in  the  manner  noted  in  detail,  in  Table  XXI  and  illustrated  in 
Fig.  1324. 

The  floor  and  side  walls  of  the  subway  below  ground  or  mean  high 
water,  when  passing  through  earth,  also  the  roof  of  stations,  were 
waterproofed  by  the  brick-in-mastic  system.  This  consisted  of 
one  or  two  courses  of  ordinary  building  brick  embedded  in  mastic. 
The  mastic  was  composed  of  a  minimum  of  one-third  asphalt  and 


354 


WATERPROOFING  ENGINEERING 


two-thirds  sand  and  cement,  or  sand  and  limestone  dust.  It  was 
mixed  hot  on  the  work  in  round-bottom  iron  kettles  of  50-  and  100- 
gallon  capacities  (see  Fig.  77)  at  a  temperature  not  exceeding  375 
deg.  Fahr. 

IPlvWP  One  or  more  "Layers  of  4  Concrete         2  Layers  of  Brick  in  Asphalt    i  ply  W  P 

„          '_     ',     '        /      Brick  in  A&phalt .;/ |   |       V     / / !_,   '  j 

2  Min. 


2"Min 


3  Ply  W. P.          i    4  Concrete 


AT  STATIONS 

4  Concrete     2  Layers  of  Brick  in  Asphalt  j  p\y  w.P. 


Concrete 


6  Concrete 


„          - 
3  Concrete 


BETWEEN  STATIONS 

FIG.  132  A. 

In  applying  the  brick-in-mastic  to  the  floor  of  the  subway,  the 
surface  of  the  concrete  bed,  which  was  generally  from  4  to  6  inches 
thick,  was  covered  with  a  single  ply  of  waterproofing  felt  or  fabric, 
and  its  surface  completely  mopped.  This  served  as  a  dry  ply  upon 
which  to  place  the  brick-in-mastic  envelope. 


WATERPROOFING  APPLIED 


355 


Two  courses  of  brick-in-mastic  were  applied  to  the  floor  and 
together  had  a  minimum  depth  of  5  inches.  The  thickness  of  the 
various  brick-coverings  of  mastic  was  not  less  than  f  of  an  inch 
(see  Fig.  133). 

On  side-wall  construction,  the  vertical  surface  of  the  excavation 
was  first  carefully  faced  with  concrete.  Forms  were  placed  8  inches 


FIG.  133. — Showing  Application  of  First  and  Second  Layers  of  Brick-in-Mastic 
and  Method  of  Sliding  Bricks  into  Place.  (Note  Mastic  Covering  Finished 
Portion  between  the  Two  Posts.) 


from  this  facing  and  the  brick  and  mastic  laid  therein,  as  follows. 
A  quantity  of  mastic  was  poured  into  the  space  and  bricks  laid  in 
it  on  their  largest  bed  and  in  a  double  row,  leaving  a  minimum  of 
f-inch  joints  around  all  faces.  After  cooling,  the  forms  were  removed 
and  the  main  concrete  wall  of  the  subway  was  built  against  the  mastic 
wall.  No  leaks  developed  where  the  brick-in-mastic  envelope  was 
used. 


356  WATERPROOFING  ENGINEERING 


EXAMPLES  OF  INTEGRAL  WATERPROOFING  APPLICATIONS 

Waterproofing  Reinforced  Concrete  Reservoir.*  In  renovating 
a  1,000,000-gallon  reinforced  concrete  reservoir  at  New  Ulm,  Minn., 
watertightness  was  secured  in  the  structure  by  exercising  special 
care  during  construction  to  grade  the  concrete  aggregate.  Pebbles, 
varying  in  size  from  J  to  2J  inches  screened  from  a  gravel  bank,  were 
used  in  the  floor  and  walls,  as  experiments  had  shown  that  these 
pebbles  made  a  denser  concrete  than  broken  stone.  To  reduce  the 
permeability  of  the  concrete  to  a  minimum,  however,  20  pounds  of 
hydrated  lime  was  used  to  every  barrel  of  cement.  After  the  forms 
were  removed,  the  walls  were  brushed  and  cleaned  with  steel  brushes, 
and  two  coats  of  1  :  2  cement  mortar,  about  |  inch  thick,  water- 
proofed by  the  addition  of  10  per  cent  of  finely  powdered  iron,  were 
applied.  The  floor  was  treated  with  a  slush  coat  of  1  :  2  mortar 
which  after  setting  received  a  brush  coating  of  waterproofed  mortar. 
After  water  was  let  in  some  leaking  took  place  and  cracks  developed 
which  were  finally  remedied  and  the  reservoir  was  rendered  watertight. 

Concrete  Tank  at  Duxbury,  Mass.  A  reinforced  concrete  tank 
in  Duxbury,  Mass.,  f  40  feet  inside  diameter  and  35  feet  high  was 
made  watertight  by  using  a  rich*  concrete  with  an  addition  of  hydrated 
lime.  The  bottom  is  a  reinforced  concrete  slab  built  in  two  12-inch 
layers,  the  lower  one  of  1:2:4  concrete  and  the  upper  one  of 
1  :  1J  :  3  mixture  with  the  addition  of  5  per  cent  hydrated  lime. 
The  walls  are  of  1  :  1  :  2  concrete  with  5  per  cent  of  cement  replaced 
with  hydrated  lime,  and  the  dome  is  of  1  :  2  :  4  concrete.  In  order 
to  prevent  water  from  passing  through  the  joints  made  by  each  day's 
work,  thin  steel  bands  4  inches  in  width  were  inserted  so  that  one- 
half  of  the  width  was  embedded  in  the  old  work  and  one-half  in  the 
new. 

EXAMPLES  OF  SELF-DENSIFIED  CONCRETE  APPLICATIONS 

Reinforced  Concrete  Filter  Plant.  In  the  construction  of  the 
filter  plant  at  Lancaster,  Pa.,  in  1905,  a  pure-water  basin  and  several 
circular  tanks  were  constructed  of  reinforced  concrete.  The  pure- 
water  basin  is  100  feet  wide  by  200  feet  long  and  14  feet  deep,  with 
buttresses  spaced  12  feet  6  inches  center  to  center.  The  walls  at 
the  bottom  are  15  inches  thick,  and  12  inches  thick  at  the  top.  Four 
circular  tanks  are  50  feet  in  diameter  and  10  feet  high,  and  eight 

*  Engineering  Record,  December  17,  1910,  Vol.  62,  No.  25. 
t  Engineering  News,  Vol.  75,  May  6,  1916. 


WATERPROOFING  APPLIED  357 

tanks  are  10  feet  in  diameter  and  10  feet  high.  The  walls  are  10 
inches  thick  at  the  bottom  and  6  inches  at  the  top.  A  wet  mixture 
of  1  part  cement,  3  parts  sand,  and  5  parts  stone  was  used.  No 
waterproofing  material  was  used  in  the  construction  of  the  tanks,  and 
when  tested,  two  of  them  were  found  to  be  watertight,  the  other  two 
had  a  few  leaks  where  wires,  which  had  been  used  to  hold  the  forms 
together,  had  pulled  out  when  the  forms  were  taken  down.  These 
holes  were  stopped  up  and  no  further  trouble  was  experienced.  In 
constructing  the  floor  of  the  pure-water  basin  a  thin  layer  of  asphalt 
was  used,  but  no  waterproofing  material  was  used  in  the  walls,  and 
both  were  found  to  be  watertight. 

Reinforced  Concrete  Watertank.  A  reinforced  concrete  water- 
tank,  10  feet  inside  diameter  and  43  feet  high,  designed  and  con- 
structed by  W.  B.  Fuller  at  Little  Falls,  N.  J.,  has  some  remarkable 
construction  features.  It  is  15  inches  thick  at  the  bottom  and 
10  inches  thick  at  the  top.  The  tank  was  built  in  eight  hours,  and 
is  a  perfect  monolith,  all  concrete  being  dropped  from  the  top, 
or  43  feet  at  the  beginning  of  the  work.  The  concrete  was  mixed 
very  wet,  the  mixture  being  1  part  cement,  3  parts  sand,  and  7  parts 
broken  stone.  No  plastering  or  waterproofing  of  any  kind  was  used, 
but  the  tank  was  found  to  be  absolutely  watertight.  The  large 
aggregate  was,  however,  scientifically  graded. 

EXAMPLES  OF  GROUTING  APPLICATIONS 

Waterproofing  Pressure  Tunnels.  Some  of  the  tunnels  of  the 
Catskill  Aqueduct  of  New  York  City  *  were  made  watertight  by 
grouting  behind  the  tunnel  lining.  This  grouting  followed  the  con- 
creting within  a  period  of  two  to  three  months,  when  the  concrete 
had  attained  sufficient  strength  to  resist  high  grouting  pressures. 
Air-stirring,  grouting  machines  of  the  Canniff  type,  holding  about 
25  gallons,  were  generally  employed  for  this  work,  though  a  few 
mechanically  stirred  Cockburn  machines  of  the  same  capacity  were 
tried.  For  low-pressure  work,  by  which  the  voids  about  the  lining 
were  filled,  air  direct  from  the  compressor  plants  was  used;  for  the 
high-pressure  work  the  air  pressure  was  raised  by  means  of  auxiliary 
high-pressure  air  compressors. 

For  filling  the  voids  in  the  dry  packing  and  the  cavities  and 

shrinkage  spaces  left  over  the  arch  concrete,  the  grout  was  mixed 

in  the  proportion  of  one  cement  to  one  sand,  with  an  equal  volume  of 

water,  and  forced  in  under  pressure  of  80  to  100  pounds  or  more 

*  Engineering  News,  Vol.  73,  February  4,  1915. 


358  WATERPROOFING  ENGINEERING 

per  square  inch,  depending  on  the  ground-water  head.  Neat  cement 
was  employed  in  filling  the  drip  pans  and  other  thin  cavities.  See 
Fig.  134  for  details.  No  masonry  cutoff  walls  were  built  to  stop 
the  grout,  except  where  dry  packing  was  to  be  filled,  and  no  attempt 
was  then  made  to  make  them  tight  at  the  crown  of  the  arch.  Work 
was  started  at  some  favorable  point  where  the  grout  would  of  itself 
make  a  cutoff  and  carried  steadily  on,  connecting  to  each  pipe  in 
turn.  The  general  practice  was  to  commence  grouting  through  the 
pipes  nearest  the  invert,  and  upward  to  the  arch.  On  completion 
of  the  low-pressure  grouting,  neat-cement  grout,  generally  mixed 
in  the  proportion  of  four  to  eight  volumes  of  water  to  one  of  cement, 
though  sometimes  containing  as  much  as  fifteen  volumes  of  water 
to  one  of  cement,  was  forced  into  many  of  the  pipes  previously  grouted 
and  into  the  deep-seated  pipes,  under  pressures  of  250  to  3'00  pounds 
per  square  inch,  to  fill  the  small  spaces  and  seams  in  the  rock  about 
the  lining.  The  cost  of  grouting  the  tunnels  to  watertightness  ran 
from  $2.50  to  $3  per  lineal  foot  of  tunnel,  including  the  costs  for  plant, 
materials  and  labor.  The  tunnel  was  made  remarkably  watertight 
as  a  result  of  these  operations. 

Ashokan  Dam  CutofL*  In  making  watertight  the  cutoff  wall  for 
the  Ashokan  Dam  on  the  Catskill  Aqueduct,  a  row  of  3-inch  grouting 
holes  were  drilled  20  feet  below  the  bottom  of  the  trench,  reaching 
the  greatest  depth  at  which  the  boring  tests  had  indicated  the 
presence  of  seams.  Similar  grouting  holes  were  drilled  to  about 
the  depth  of  the  cutoff  to  insure  the  sealing  of  any  seams  that  might 
exist  in  the  rock  under  the  main  body  of  the  dam.  Two-inch  iron 
pipes  were  cemented  in  the  tops  of  the  drill  holes  and  carried  up  into 
the  masonry  to  permit  grouting  when  the  dam  had  reached  sufficient 
height  to  withstand  the  pressure  of  the  grout.  These  grout  pipes 
were  then  grouted  with  neat-cement  by  the  use  of  a  Cockburn  Bar- 
row grout  machine  of  4  cubic  feet  capacity,  operated  under  a  pres- 
sure of  25  to  80  pounds.  The  results  were  entirely  satisfactory. 

Rondout  Pressure  Tunnel.  In  constructing  the  Rondout  Pres- 
sure Tunnel  of  the  Catskill  Aqueduct,  several  wide  shafts  were  sunk. 
These  shafts  had  to  be  waterproofed  to  facilitate  operations;  espe- 
cially one  shaft  in  which  the  seams  were  large  and  many.  Twenty- 
seven  vertical  holes  were  drilled,  14  to  20  feet  deep  and  capped  with 
pipes  and  valves  for  the  purpose  of  grouting  these  seams.  A  battery 
of  4  Canniff  tank-grouting  machines  were  set  up  at  the  top  with 
2^ -inch  pipe  in  the  shaft  and  a  2-inch  hose  connection  at  the  bottom. 
At  first  the  grout  leaked  back  into  the  shaft  in  considerable  volume. 

*  "  Catskill  Water  Supply  of  New  York  City,"  by  Lazarus  White,  C.  E. 


WATERPROOFING  APPLIED 


359 


360  WATERPROOFING   ENGINEERING 

Various  methods  were  then  tried  to  prevent  this  leakage — the  use 
of  oats,  bran,  and  ground  horse  manure,  the  latter  finally  clogging 
the  seams  and  stopping  most  of  the  leakage  in  the  shaft.  The 
shallower  holes  took  2900  bags  of  cement  and  the  20-foot  holes  only 
60  bags.  This  grouting  proved  to  be  so  successful  that  it  was  deter- 
mined to  grout  some  of  the  deeper  seams  known  to  be  porous  and 
water-bearing. 

EXAMPLES  OF  SPECIAL  WATERPROOFING  APPLICATIONS 

Harlem  River  Tunnels.  The  use  of  cast-iron,  cast-steel,  and 
iron  and  steel  plates  for  waterproofing  is  not  common  but  none  the 
less  quite  practicable.  Fig.  135  shows  half-sections  through  the 
steel  lining  used  as  waterproofing  for  the  Harlem  River  Tunnel 
tubes  connecting  the  Lexington  Avenue  subway  between  Manhattan 
and  Bronx  boroughs,  forming  a  part  of  the  Dual  Subway  System  in 
New  York  City.  The  steel  (Fig.  135^4.)  was  sunk  in  a  prepared 
channel  in  the  river  bed  and  surrounded  with  concrete  within  and 
without.  This  created  an  excellent  watertight  tunnel.*  The  same 
is  quite  true  of  the  cast-iron  and  cast-steel  tunnel  linings  used  on 
the  Pennsylvania  railroad  tunnels  under  the  Hudson  River  and  the 
New  York  Subway  tunnels  under  the  East  River.  See  Fig.  136  for 
details  of  the  type  of  cast-steel  tunnel  segments  used  on  the  two 
latter  structures. 

These  segmental  linings  make  an  effective  waterproofing,  though 
the  joints  are  not  absolutely  watertight.  The  leakage,  however, 
is  insignificant,  as  proven  by  the  following  fact.  In  the  above- 
named  tunnels,  a  sump  of  some  form  is  provided  at  the  lowest  point 
of  each  tunnel  or  pair  of  tunnels  and  pumped  out  when  necessary 
by  pumps  regularly  installed.  This  showed  that  the  daily  leakage 
into  the  5J  miles  of  river  tunnels  of  the  Pennsylvania  Railroad  is 
2300  gallons.  The  magnitude  of  this  may  be  better  appreciated  by 
stating  that  the  entire  amount  of  leakage  for  one  day  would  be 
removed  in  one  or  two  minutes  by  a  pump  of  the  capacity  ordinarily 
used  by  contractors  for  foundations.! 

Rubber  Sheet  used  on  Waterworks  Reservoir,  t  A  reservoir 
built  in  Bellaire,  Ohio,  in  1905,  was  put  into  successful  operation 

*  See  paper  by  Howard  B.  Gates,  "  Harlem  River  Crossing  of  the  Lexington 
Avenue  Subway."  The  Municipal  Engineers  Society's  Journal,  Vol.  1,  No.  6, 
New  York  City,  December,  1915. 

t  Alfred  Noble,  in  Journal  of  the  Franklin  Institute,  Vol  175,  p.  383. 

t  Engineering  Record,  June  3,  1916. 


WATERPROOFING  APPLIED 


361 


HALF  SECTION- AT  DIAPHRAGM 
SHOWING  STEEL  DETAILS 


Symmetrical 
about  this  line 


HALF  SECTION  BETWEEN 
DIAPHRAGMS  SHOWING  CONCRETE  DETAILS 


FIG.  135.— Harlem  River  Tunnel  Tubes,  as  Built. 


362  WATERPROOFING  ENGINEERING 

for  the  first  time  in  eleven  years  after  its  construction.  This  was 
made  possible  only  after  it  was  waterproofed  by  a  unique  method. 
Unstable  foundations  had  caused  cracks,  particularly  in  one  corner 
of  the  reservoir,  which  defied  all  the  many  attempts  to  make  the 
structure  watertight  until  the  following  inexpensive  method  was  used. 
A  strip  of  sheet  rubber,  stretching  30  feet  long  by  3  feet  wide  by 
|  inch  thick,  was  placed  in  the  corner  of  the  basin  covering  the  crack. 
A  box,  built  around  this  rubber-covering  and  filled  with  soft  mud, 
kept  the  sheet  in  place.  Another  large  crack,  in  the  bottom  of  the 


FIG.  135A. — Steel  Tubes  for  Harlem  River  Tunnel,  Lexington  Avenue  Subway, 

before  Sinking. 


basin,  was  also  covered  with  a  strip  of  rubber  and  held  in  place  by  a 
cement  mortar  covering.  The  basin  was  then  filled  with  water,  and 
it  was  found  that,  although  the  crack  in  the  wall  opened  YQ  mcn 
still  further,  there  was  no  leakage.  This  method  was  suggested  and 
carried  into  effect  by  Mr.  F.  J.  Lewis,  a  resident  of  Bellaire. 

Timber  Sheeting  Waterproofing  for  Subaqueous  Tunnels.* 
Referring  to  Fig.  137,  in  which  timber  sheeting  constitutes  the 
waterproofing  for  a  subaqueous  tunnel,  the  author  believes  that  if 
the  form  of  tunnel  construction  indicated  is  at  all  practicable,  the 

*  Proceedings  of  the  American  Society  of  Civil  Engineers  for  November,  1914. 


WATERPROOFING  APPLIED 


363 


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WATERPROOFING  ENGINEERING 


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WATERPROOFING  APPLIED  365 

proposed  waterproofing  method  seems  impracticable.  To  build  a 
subaqueous  tunnel  and  to  waterproof  it  with  creosoted,  tongued 
and  grooved  yellow  pine  planking,  pinned  on  the  outside  of  the  struc- 
tural material  is  a  unique  conception,  though  never  attempted,  to 
the  author's  knowledge.  This  form  of  waterproofing  and  its  applica- 
tion, Mr.  D.  D.  McBean,  the  originator,  believes  will  be  possible  by 
the  use  of  his  patented  "  Subaqueous  Working  Chamber  "  for  con- 
structing the  tunnel. 

Basement  Waterproofed  with  Sheet  Lead  Lining.  The  excava- 
tion for  the  basement  of  the  Proctor  &  Gamble  Mfg.  Co.'s  building  on 
Staten  Island,  N.  Y.,  was  made  in  red  clay.  Due  to  the  existence  of 
swampy  ground  on  the  site,  considerable  seepage  had  to  be  contended 
against  and  prevented  from  percolating  into  the  cellar.  The  floor 
and  walls  were  built  of  concrete,  and  were  waterproofed  by  the 
application  on  the  inside  of  1-ply  sheet  lead  weighing  3  pounds  per 
square  foot.  This  sheet  lead  was  also  applied  to  the  columns,  the 
strips  being  carefully  soldered  together  so  as  to  make  a  seamless  pan 
of  the  whole.  On  the  floor  the  sheet  lead  was  laid  on  a  1-inch  sand 
cushion,  and  on  the  wall,  directly  against  the  concrete.  The  entire 
lead  membrane  was  then  protected  with  a  5-inch  layer  of  concrete. 
The  results  obtained  by  this  method  of  waterproofing  were  quite 
satisfactory. 

Cement-clay  Cover  for  Hudson  and  Manhattan  Railroad  Tunnel. 
A  waterproofing  method,  in  which  an  impervious  layer  of  cement 
and  clay  was  interposed  between  water-bearing  ground  and  a  concrete 
substructure,  was  used  in  the  recent  addition  to  the  Pavonia  Avenue 
station  of  the  Hudson  and  Manhattan  Railroad  in  Jersey  City,  N.  J. 
The  work  consisted  in  excavating,  by  tunneling  methods  and  sub- 
sequently lining  with  concrete,  a  station  opening  in  a  water-bearing 
stratum  200  feet  from  the  Hudson  River  bulkhead  line  and  50  feet 
below  mean  sea  lavel.  It  was  imperative  that  the  concrete  lining 
be  watertight,  but  it  had  been  the  experience  of  the  engineers  in 
building  the  original  tunnel  that  it  was  impossible  in  working  under 
air  pressure  to  use  any  applied  waterproofing  mats  on  account  of  the 
danger  to  workmen  from  fumes;  expected  expansion  and  contrac- 
tion with  consequent  cracks  forbade  the  use  of  any  integral  water- 
proofing material. 

It  had  been  noted  that  all  of  the  river  tunnels  which  rest  in 
river  clay  were  quite  watertight,  and  it  was  believed  that  if  a  com- 
plete coating  of  clay  could  be  obtained  exterior  to  the  tunnel  lining, 
no  more  nearly  perfect  or  complete  waterproofing  could  be  secured. 
The  difficulty  with  any  clay  application  was  that  when  wet  and  soft 


366  WATERPROOFING  ENGINEERING 

the  clay  would  change  its  form  by  squeezing.  Therefore,  experi- 
ments were  made'  with  clay  mixed  with  sufficient  Portland  cement 
to  hold  its  form  when  set. 

Hudson  River  silt,  which  is  a  finely  pulverized  clay  with  a  con- 
siderably larger  proportion  of  silica  than  ordinary  clay,  was  dried 
and  mixed  with  equal  proportions  of  Portland  cement,  applied  through 
the  medium  of  a  cement  gun  as  a  heavy  coating  on  every  portion  of 
exposed  timbering  and  lagging  in  the  tunnel.  This  produced  a  layer 
of  impervious  plaster  about  2  inches  thick  against  which  the  con- 
crete lining  of  the  tunnel  was  placed.  The  method  has  proved  suc- 
cessful, the  station  structure  being  practically  dry  under  an  extreme 
head  of  salt  water. 

Iron-lined  Coal  Pits.*  In  constructing  concrete  coal  pits  for 
railway  coaling  stations  of  the  elevator  type  it  is  essential  that  the 
pit  (for  the  elevator  bucket)  should  be  watertight.  The  pit  is 
usually  considerably  below  the  ground-water  level  and  is  subject  to 
pressure,  and  when  once  put  in  operation  it  is  a  matter  of  difficulty 
and  expense  to  get  at  it  and  make  repairs. 

A  plan,  which  has  been  used  with  success,  is  to  place  within  the 
concrete  a  steel  boot  or  tank  with  joints  soldered  in  the  field.  A 
6-inch  thickness  of  concrete  is  placed  first,  and  then  the  steel  boot 
is  set  in  position  and  the  sections  soldered.  When  this  has  beon 
made  watertight  it  is  lined  with  6  inches  of  concrete.  All  attach- 
ments, bolts  ladders,  etc.,  are  set  in  this  inner  lining. 

Fig.  138  shows  such  a  pit  having  a  boot  6  feet  11  inches  by  11 
feet  6  inches  and  a  height  of  11  feet,  its  top  being  above  ground- 
water  level.  It  is  made  of  No.  20  galvanized  iron,  and  the  expecta- 
tion is  that  if  the  metal  should  rust  in  course  of  time  it  would  still 
form  a  waterproof  diaphragm  by  combination  with  the  cement. 
The  concrete  is  a  1  :  5  mix,  made  with  gravel,  and  mixed  moderately 
wet.  The  use  of  a  similar  boot  composed  of  burlap  and  asphaltic 
composition  has  given  fair  success.  To  place  a  waterproof  lining 
outside  of  the  concrete  would  involve  greater  excavation  and  addi- 
tional form  work. 

Calking  Tunnels  of  Pennsylvania  Railroad,  f  In  making  water- 
tight the  East  River  Tunnels  of  the  Pennsylvania  Railroad,  the  joints 
between  the  cast-steel  segments  composing  the  tunnel  rings  were  at 
first  calked  with  a  mixture  of  iron  filings  and  salammoniac  in  the 
proportions  by  weight  of  400  to  1.  The  calking  was  done  by  hand. 

*  Engineering  News,  Vol.  76,  October  5,  1916. 

t  "  The  Subways  and  Tunnels  of  New  York,"  by  G.  H.  Gilbert,  L.  I.  Wight- 
man  and  W.  L.  Saunders, 


WATERPROOFING  APPLIED 


367 


Later,  lead  wool,  calked  cold  by  pneumatic  hammers,  was  substituted 
with  better  results.  This  calking  preceded  the  placing  of  a  concrete 
lining  about  1  foot  thick  inside  the  iron  rings.  One-to-one  grout 
was  then  forced  between  the  top  of  this  inner  concrete  lining  and  the 
outer  iron  segments.  Great  care  was  exercised  in  this  work  and  very 
good  results  were  obtained. 

Waterproofing  of  the  North  River  Tunnels  of  the  Pennsylvania 
Railroad  consisted  in  forming  a  rust  joint  (with  a  mixture  of  sal- 


Coal  Car  Track 


FIG.  138.— Concrete  Coal  Pit  Waterproofed  with  Sheet  Steel  Boot. 

ammoniac  and  iron  borings)  between  the  plates  of  the  metal  lining 
forming  the  tubes,  and  in  taking  out  each  bolt  and  placing  around 
the  shank  under  the  washer  at  each  end  a  grommet  made  of  yarn 
soaked  in  red  lead.  Before  calking  with  the  rust  mixture  the  joints 
were  cleaned.  The  usual  mixture  for  the  joints  was  2  pounds  of 
salammoniac,  1  pound  of  sulphur  and  250  pounds  of  iron  filings  or 
borings.  Air  hammers  were  used  with  advantage  in  calking  this 
mixture  into  the  joints.  The  results  were  variable  and  not  always 
satisfactory. 


CHAPTER  XI 


COST  DATA   ON   MATERIALS,   IMPLEMENTS,   AND   LABOR 

PLANNING  AND  ESTIMATING 

Importance  of  Accurate  Estimates.  Record  costs  do  not  always 
agree  with  the  estimates  given  for  any  particular  work  because  anal- 
ysis for  systematizing  labor  operations  preceding  the  making  of  such 
estimates  are  too  often  insufficient,  or  neglected  altogether.  This  is 
illustrated  by  the  enormous  variations  in  bids  received  from  contrac- 
tors for  the  same  job.  For  example,  the  bids  received  for  waterproof- 
ing a  section  of  the  New  York  Dual  Subway  in  1915  were  as  follows: 


A. 

B. 

C. 

D. 

'   E.' 

F. 

Maximum 
Difference 
(Per  cent). 

Fabric  membrane,  1-ply  

$0.50 
liOO 
2.00 
25.00 
7.00 

$0.40 
1.20 
1.60 
20.00 
6.50 

$0.45 
1.80 
2.40 
18.00 
7.50 

$0.35 
.75 
1.40 
22.00 
6.00 

$0.30 
.90 
1.50 
20.00 
8.00 

$0.41 
1.10 
1.83 
16.00 
7.25 

66 
140 
71 
56 
33 

Fabric  membrane,  3-ply  

Fabric  membrane,  6-ply  

Brick-in-mastic,  cu.  yd  
Protective  concrete,  cu.  yd  

On  another  section  of  the  same  subway,  the  following  bids  for 
waterproofing  work  were  received: 


A. 

B. 

C. 

D. 

E. 

Maximum 
Difference 
(Percent). 

Fabric  membrane,  1-ply  

$0.30 
.70 
1.30 
25.00 
10.00 

$0.35 
1.20 
1.50 
29.00 
7.50 

$0.40 
1.10 
1.40 
20.00 
9.00 

$0.50 
.90 
2.00 
18.00 
8.50 

$0.6C 
.80 
2.25 

8.00 

100 
71 

73 
61 
33 

Fabric  membrane  3-ply       

Fabric  membrane  6-ply           

Brick-in-mastic  cu  yd 

Protective  concrete,  cu.  yd  :  .  . 

To  account  for  such  marked  differences  in  estimate  figures  several 
items  enter  into  consideration;  usually  and  mainly,  these  are  the 
result  of  a  wrong  estimate  of  labor  cost.  The  methods  of  manage- 
ment undoubtedly  affect  the  cost  to  a  very  large  extent,  but  this 
hardly  explains  the  difference  of  100  and  140  per  cent  in  the  esti- 
mated costs  submitted  by  the  different  contractors.  The  variations 

368 


COST  DATA  ON   MATERIALS,   IMPLEMENTS,   AND   LABOR    369 

are  more  probably  due  to  the  following  four  causes:  (1)  Inaccurate 
estimate  of  volumes  or  cost  of  materials;  (2)  inaccurate  estimates 
of  overhead  costs  and  profits;  (3)  manipulation  of  estimate  prices; 
(4)  inaccurate  estimates  of  labor  costs.  Material  costs  usually  are 
figured  without  difficulty,  and  these,  except  during  abnormal  busi- 
ness conditions,  are  reasonably  constant.  Hence,  only  mistakes  are 
chargeable  here.  The  variation  in  overhead  charges  by  two  different 
estimators  may  be  large  because  many  contractors  do  not  properly 
charge  or  divide  their  overhead  items,  but  this  difference  on  any  one 
job  cannot  account  for  more  than  15  or  20  per  cent.  Manipulation 
of  estimate  prices,  that  is,  figuring  high  on  one  item  and  low  on  an- 
other, unless  done  with  great  skill  and  foresight,  proves  a  profitless 
process  so  often  that  it  is  not  generally  resorted  to.  This  would, 
however,  in  some  cases,  account  for  about  50  per  cent  of  the  varia- 
tion. Obviously,  then,  the  big  variations  must  be  in  the  estimated 
labor  cost.  And  this  indeed  is  the  item  on  which  money  is  usually 
made  or  lost  in  contracting. 

Accurate  Estimates  Dependent  on  Accurate  Methods.  Accurate 
estimates  by  architects,  engineers,  and  contractors  should  be  made 
a  matter  of  careful  study.  An  appreciable  saving  would  always 
result  in  the  substitution  of  accurate  methods  for  guesswork  in  esti- 
mating., Mr.  Sanford  E.  Thompson,  Consulting  Engineer,*  makes 
the  following  remarks  in  regard  to  the  reduction  of  general  construc- 
tion costs,  which  are  also  applicable  to  waterproofing  costs. 

"  Accurate  cost  keeping  is  of  value  in  following  up  construction 
costs  from  day  to  day,  in  showing  up  waste  labor  and  in  providing 
a  mark  for  the  attainment  of  superintendents  and  foremen.  Unless 
cost  knowledge  is  in  the  form  of  small  units,  such  comparisons  cannot 
be  made  satisfactorily. 

''  To  get  the  full  benefit  of  a  knowledge  of  unit  costs,  and  in  fact 
for  this  the  knowledge  must  be  even  more  thorough  and  include  the 
unit  times  of  performing  the  various  operations,  it  must  be  utilized 
in  the  planning  of  the  work  in  advance  and  in  distributing  materials 
and  jobs;  in  selecting  materials  and  methods  which  will  result  in 
lower  labor  costs;  in  adapting  the  construction  plant  to  the  special 
conditions;  and,  carried  to  its  ultimate  end,  in  laying  out  jobs  for 
the  workmen  and  giving  them  a  reward  for  accomplishment. 

"  Such  management  as  this  involves  the  adoption  of  factory 
methods  in  construction.  Already  the  need  of  this  is  being  recog- 
nized, but  only  to  a  limited  degree. 

"•Full  economy  in  construction,  however,  will  only  be  attained 
*  Engineering  and  Contracting,  March  1,  1916,  p.  221. 


370  WATERPROOFING  ENGINEERING 

as  the  builder  discards  the  haphazard  rule-of -thumb  method  and  con- 
siders his  job  with  a  view  to  thorough  analysis,  planning  functional 
methods,  and  a  complete  study  of  details.  By  such  methods  as 
these  will  the  labor  of  construction  be  brought  to  a  more  scientific 
basis  and  more  nearly  on  a  par  with  the  material  end  of  the  work." 

LABOR  AND  MATERIALS 

Waterproofing  Labor,  Contracters  and  Manufacturers  Graded. 
Among  waterproofing  concerns  there  are  to  be  found  the  following 
classes:  (1)  Waterproofing  manufacturers  who  manufacture  and 
assume  responsibility  for  the  quality  and  effectiveness  of  the  water- 
proofing material;  (2)  Manufacturing  waterproof ers  who  manu- 
facture and  apply  the  waterproofing  material  under  a  guarantee; 
(3)  waterproofing  contractors  who  buy  the  waterproofing  material 
ready  made,  supply  the  labor,  and  supervise  and  guarantee  the 
work;  (4)  waterproofing  subcontractors  who  often  are  furnished 
with  the  waterproofing  materials,  but  always  supply  the  labor,  and 
give  personal  supervision  to  the  work. 

Some  of  the  concerns  included  under  the  above  classes  are  not 
sufficiently  responsible  or  experienced,  hence  it  is  often  advisable  to 
employ  an  experienced  waterproofing  inspector  on  the  work,  espe- 
cially when  the  magnitude  of  the  work  warrants  the  expense.  Where 
this  is  not  the  case,  experience  has  proven  the  advisability  of  con- 
tracting for  the  waterproofing  work  with  a  reputable  and  highly 
responsible  waterproofing  concern  but  always  under  a  very  specific 
guarantee. 

Many  waterproofing  concerns  maintain  laboratories  and  staffs 
of  engineers  who  co-operate  with  the  contractor,  or  builder,  in  deter- 
mining the  proper  system  and  materials  for  waterproofing  a  particu- 
lar structure.  The  service  is  often  given  gratis.  In  consequence, 
the  advice,  or  information,  is  not  always  impartial,  and  it  seems 
advisable  that  the  buyer,  builder,  architect,  or  engineer,  should 
investigate  somewhat  for  himself.  The  result  may  not  only  be  an 
improved  design  but  often  a  reduction  in  the  cost  of  waterproofing 
the  structure. 

The  labor  employed  on  waterproofing  work  is  also  divided  into 
several  classes,  as  follows:  (1)  Foremen,  who  are  men  generally  of 
large  experience  in  waterproofing  work;  (2)  Waterproof  ers,  men  who 
do  the  actual  waterproofing  work,  such  as  laying  the  brick  and 
mastic  courses,  sheet  mastic,  or  applying  bituminous  membranes; 
(3)  helpers,  men  who  help  the  waterproofers  and  incidentally  learn 
the  trade;  (4)  Kettlemen,  men  who  tend  the  kettles  in  which  the 
bitumen  is  heated  or  the  mastic  is  made  up;  (5)  laborers,  men  who 


COST  DATA  ON   MATERIALS,   IMPLEMENTS,  AND  LABOR    371 

carry  the  bricks,  wood,  etc.,  to  the  waterproof ers  and  kettlemen, 
and  perform  all  the  unskilled  labor  required;  (6)  roofers,  men  who 
mainly  waterproof  roofs  of  buildings;  (7)  roofers'  helpers,  men  who 
assist  the  roofers.  In  none  of  these  divisions  is  any  extraordinary 
skill  required.  Indeed,  in  the  application  of  all  waterproofing  care 
and  judgment  are  mostly  required. 

It  is  not  necessary  to  employ  men  of  a  particular  trade  to  do  water- 
proofing of  a  particular  kind,  but  it  is  very  essential  to  employ  men 
with  some  experience  in  the  particular  branch  of  waterproofing. 
For  example,  in  waterproofing  a  structure  by  the  application  of  a 
brick-in-mastic  envelope,  it  is  not  necessary  to  employ  a  bricklayer 
for  this  purpose,  because  no  special  bond  of  brick,  nor  refinement  of 
line  is  required,  as  in  building  construction;  but  experience  in  hand- 
ling mastic  and  properly  laying  up  mastic  courses  is  necessary  for 
good  results.  This,  however,  can  often  be  done  by  the  average 
waterproof er  after  a  short  apprenticeship.  Besides,  the  difference 
in  wages  between  bricklayers  and  waterproofers  would  materially 
affect  the  contract  price  of  a  particular  waterproofing  job. 

The  general  cost  of  waterproofing  labor  depends  to  a  certain 
extent  upon  the  locality  of  the  work,  the  nationality  of  the  workmen, 
but  more  particularly,  of  course,  upon  the  character  of  the  work 
performed. 

COST  DATA  TABLES 

The  cost  of  most  standard  waterproofing  materials,  like  other 
building  materials,  fluctuates  with  the  market.  The  cost  of  patented 
or  special  waterproofing  materials  depends  generally  on  the  quantity 
bought. 

In  buying  waterproofing  materials,  it  should  be  the  aim  of  those 
responsible,  to  buy  materials  that  are  either  well-known  or  of  proven 
efficiency  because  in  the  end  they  prove  to  be  the  cheapest.  Some 
concerns  make  a  practice  of  renaming  standard  materials  and  selling 
them  at  vastly  inflated  prices.  It  is  no  simple  matter  to  guard  against 
this,  but  when  large  quantities  of  waterproofing  materials  are  to  be 
bought,  it  will  pay  those  concerned  to  look  into  the  standard  materials 
on  the  market  before  buying  any  special  ones.  This  has  particular 
reference  to  materials  used  in  the  surface  coating  and  integral 
systems  of  waterproofing,  and  joint-filling  compounds. 

In  the  following  tables  will  be  found  the  cost  of  waterproofing 
materials,  labor,  and  implements  for  the  year  1914.  These  tables 
are  compiled  with  more  than  approximate  exactness.  Certain  other 
information  is  included  which  will  be  found  helpful  in  estimating 
and  ordering  materials.  For  the  duration  of  the  present  (1918) 


372 


WATERPROOFING  ENGINEERING 


abnormal  status  of  commerce,  the  cost  and  price  figures  given  in 
the  tables  should  be  doubled. 

Table  XXII  gives  the  average  wages,  during  1914,  of  the  differ- 
ent classes  of  workers  employed  in  the  waterproofing  industry  and 
their  range  includes  eastern  and  western  standards  of  wages.  The 
lower  figures  usually  represent  the  western  scale. 

Table  XXIII  gives  the  cost  and  weight  of  waterproofing  imple- 
ments and  tools  and  some  of  the  manufacturers  who  specialize  in 
these.  The  variation  and  range  in  cost  of  each  article  is  mainly 
due  to  the  difference  in  size  of  the  articles. 

Table  XXIV  gives  the  selling  price  at  New  York  and  weight  of 
the  most  important  and  most  extensively  used  waterproofing 
materials.  The  variation  in  prices  is  due  to  the  fact  that  they  in- 
clude the  cost  of  handling,  trucking,  etc.,  except  the  freight  rate, 
which  is  too  variable. 

Table  XXV  shows  the  cost  of  different  types  of  waterproofing 
applied.  The  profit  to  the  waterproof er  and  roofer  included  in 
most  of  these  figures  ranges  between  15  and  30  per  cent. 

Table  XXVI,  "  Cost  of  Tin  for  Flat  and  Standing  Seam  Roofing," 
enables  the  architect  and  roofer  to  calculate  the  cost  of  the  roofing 
material  from  the  cheapest  to  the  dearest  made  tin  plate.  These 
prices  depend  on  whether  the  base  plate  is  iron  or  steel,  and  upon 
the  thickness  of  the  coating  thereon.  The  coating  consists  of  an 
alloy  of  tin  and  lead,  and  the  weight  of  this  coating,  per  box  of  112 
sheets,  is  the  governing  factor  in  the  cost.  This  weight  varies  from 
8  to  40  pounds.  Those  plates  carrying  less  than  20  pounds  are  re- 
garded as  the  cheaper  grade,  while  those  carrying  more  are  in  the 
dearer  grade.  The  weight  of  coating  should  be  distinctly  called 
for  in  any  tin  roofing  specification,  and  also  stamped  on  the  tin 
sheets  by  the  manufacturer. 

TABLE  XXII.— COST  OF  WATERPROOFING  LABOR 

(!N  1914)  ' 


Class. 

Wage  Per 
Eight-hour 
Day. 

Remarks. 

Inspector. 

$4  00  to  5  00 

Municipal  and  priVate  inspection 

Foreman 

4  25  to  5  00 

Waterproof  ers  

3  .  50  to  4  .  50 

On  construction  work  of  New  York 

Kettlemen  

2  .  00  to  2  .  50 

Rapid  Transit  Subways.      Union 

Waterproofers'  helpers  .  .  '. 
Laborers 

1.75  to  2.  25 
1  50  to  2.00 

Labor. 
Unskilled  labor. 

Roofers 

3  50  to  4  .  50 

Roofers'  helpers  

2.  25  to  2.  50 

COST  DATA  ON   MATERIALS,   IMPLEMENTS,  AND  LABOR    373 


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WATERPROOFING  ENGINEERING 


TABLE  XXVI.— COST  OF  TIN   FOR   FLAT  AND   STANDING  SEAM 

ROOFING  * 


TIN  PLATES  14  BY  20. 

TIN  PLATES  20  BY  28. 

When  Tin 
Costs 
(per  Box.) 

Flat  Seam 
(Cost 
per  Square). 

Standing  Seam 
(Cost 
per  Square). 

When  Tin 
Costs 
(per  Box). 

Flat  Seam 
(Cost 
per  Square). 

Standing  Seam 
(Cost 
per  Square). 

$3.00 

$1.67 

$1.85 

$6.00 

$1.57 

$1.69 

4.00 

2.22 

2.47 

8.00 

2.10 

2.25 

5.00 

2.78 

3.09 

10.00 

2.62 

2.81 

6.00 

3.34 

3.71 

12.00 

3.15 

3.37 

7.00 

3.89 

4.32 

14.00 

3.67 

3.94 

8.00 

4.45 

4.94 

16.00 

4.20 

4.50 

9.00 

5.00 

5.56 

18.00 

4.72 

5.06 

10.00 

5.56 

6.18 

20.00 

5.25 

5.62 

11.00 

6.11 

6.80 

22.00 

5.77 

6.19 

12.00 

6.67 

7.41 

24.00 

6.30 

6.75 

*Price  per    100   square   feet  at  a  given   price   per  box  of  112   sheets — Cost  of   laying  not 
included. 


CHAPTER  XII 
PRACTICAL  TABLES 

Explanation  of  Tables.  Tables  are  very  useful,  and  in  technical 
books  indispensable,  especially  when  they  are  all  pertinent  to  the 
subject.  A  conscientious  effort  has  been  made  to  keep  the  present 
work  free  of  the  encumbrance  of  irrelevant  tables.  The  few  included 
herein  have  been  found  indispensable.  They  are  believed  to  be 
accurate  but  not  necessarily  complete,  though  sufficient  for  all 
practical  purposes. 

Table  XXVII,  "  Thermometric  Equivalents,"  converts  the  Fah- 
renheit temperature  scale  into  the  Centigrade  scale  and  vice  versa. 
This  is  often  necessary  in  the  laboratory  and  in  the  field. 

Table  XXVIII  gives  the  relative  values  of  density  and  specific 
gravity  of  liquids  heavier  than  water. 

Table  XXIX,  "  Specific  Gravity  and  Baume  for  Liquids  Lighter 
than  Water,"  shows  the  relation  of  density,  as  recorded  on  the 
Baume  scale,  to  specific  gravity  of  liquids  lighter  than  water.  Every 
liquid  lighter  than  water  has  a  definite  specific  gravity  at  a  certain 
temperature,  and  in  consequence  a  definite  density  which  is  usually 
measured  by  the  hydrometer  and  expressed  on  the  Baume  scale. 
Some  liquids,  such  as  petroleum  oils,  when  distilled  at  and  to  a  cer- 
tain temperature,  give  off  volatile  oils,  which  leave  the  residue  denser 
than  the  original;  this  denser  composition  is  indicated  by  a  corre- 
spondingly higher  reading  on  the  Baume"  scale.  This  reading  may 
be  transformed,  by  means  of  the  table,  into  an  equivalent  specific 
gravity  of  that  liquid  for  that  temperature. 

Table  XXX,  "  Specific  Gravity  and  Coefficient  of  Expansion  of 
Various  Materials,"  is  compiled  from  the  most  reliable  sources. 
Some  of  the  values  are  not  to  be  found  in  any  book,  having  been 
obtained  from  research  laboratory  tests.  A  knowledge  of  the  rela- 
tive expansion  and  contraction  of  mineral  and  organic  solids  and 
liquids  is  often  necessary  in  waterproofing  engineering. 

Table  XXXI,  "  Weight  and  Thickness  of  Burlap,  Felt,  and  Cot- 
ton Fabric  Membranes  with  Coal-tar  Pitch  Binder,"  is  based  on  water- 
proofing membranes  made  only  with  coal-tar  pitch  binder.  If 

379 


380 


WATERPROOFING  ENGINEERING 


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PRACTICAL  TABLES 


381 


TABLE  XXVIII 

Specific  Gravities  at  —-0  F.    jW^C-     Corresponding  to  Degrees  Baume*  for 
Liquids  Heavier  than  Water 


60° 
Calculated  from  the  formula,  specific  gravity       F. 


145 


145-Deg.Baume' 


Degrees 
Baume. 

TENTHS  OF  DEGREES  BAUMB. 

0 

l 

2 

3 

4 

5 

6 

7 

8 

9 

0 

1.0000 

1.0007 

1.0014 

1.0021 

.0028 

1.0035 

1.0042 

1.0049 

1.0055 

1.0062 

1 

1.0069 

1.0076 

.0083 

1.0090 

.0097 

1.0105 

1.0112 

1.0119 

1.0126 

1.0133 

2 

1.0140 

1.0147 

.0154 

1.0161 

.0168 

1.0175 

1.0183 

1.0190 

1.0197 

1.0204 

3 

1.0211 

1.0218 

.0226 

1.0233 

.0240 

1.0247 

1.0255 

1.0262 

1.0269 

1.0276 

4 

1.0284 

1.0291 

.0298 

1.0306 

.0313 

1.0320 

1.0328 

1.0335 

1.0342 

1.0350 

5 

1.0357 

1.0365 

.0372 

1.0379 

.0387 

1.0394 

1.0402 

1.0409 

1.0417 

1.0424 

6 

1.0432 

1.0439 

.0447 

1.0454 

1.0462 

1.0469 

.0477 

1.0484 

1.0492 

1.0500 

7 

1.0507 

1.0515 

.0522 

1.0530 

1.0538 

1.0545 

.0553 

1.0561 

1.0569 

1.0576 

8 

1.0584 

1.0592 

.0599 

1.0607 

1.0615 

1.0623 

.0630 

1.0638 

1.0646 

1.0654 

9 

1.0662 

1.0670 

.0677 

1.0685 

1.0693 

1.0701 

.0709 

1.0717 

1.0725 

.0733 

10 

1.0741 

1.0749 

.0757 

1.0765 

.0773 

1.0781 

.0789 

1.0797 

1.0805 

.-0813 

11 

1.0821 

1.0829 

.0837 

1.0845 

.0853 

1.0861 

1.0870 

1.0878 

1.0886 

.0894 

12 

1.0902 

1.0910 

.0919 

1.0927 

.0935 

1.0943 

1.0952 

1.0960 

1.0968 

.0977 

13 

1.0985 

1.0993 

.1002 

1.1010 

.1018 

1.1027 

1.1035 

1.1043 

1.1052 

.1060 

14 

1.1069 

1  .  1077 

.1086 

1.1094 

.1103 

1.1111 

1.1120 

1.1128 

1.1137 

.1145 

15 

1.1154 

1.1162 

1.1171 

.1180 

1.1188 

1.1197 

.1206 

1.1214 

1  .  1223 

.1232 

16 

1  .  1240 

1  .  1249 

1.1258 

.1267 

1.1271 

1.1284 

.1293 

1.1302 

1.1310 

.1319 

17 

1.1328 

1  .  1337 

1  .  1346 

.1355 

1.1364 

1.1373 

.1381 

1.1390 

1.1399 

.1408 

18 

1.1417 

1  .  1426 

1.1435 

.1444 

1  .  1453 

1  .  1462 

.1472 

1.1481 

1  .  1490 

.1499 

19 

1  .  1508 

1.1517 

1.1526 

.1535 

1.1545 

1.1554 

.1563 

1.1572 

1  .  1581 

.1591 

20 

1  .  1600 

1  .  1609 

1.1619 

.1628 

1  .  1637 

1.1647 

.1656 

1.1665 

1.1675 

.1684 

21 

1  .  1694 

1.1703 

1.1712 

.1722 

1  .  1731 

1.1741 

.1750 

1.1760 

1.1769 

.1779 

22 

1.1789 

1  .  1798 

1.1808 

1.1817 

1.1827 

1  .  1837 

.1846 

1  .  1856 

1  .  1866 

1  .  1876 

23 

1.1885 

1  .  1958 

1  .  1905 

1.1915 

1.1924 

1  .  1934 

.1944 

1.1954 

1.1964 

1.1974 

24 

1  .  1983 

1  .  1993 

1.2003 

1.2013 

.2023 

1.2033 

.2043 

1.2053 

1.2063 

1.2073 

25 

1.2083 

1.2093 

1.2104 

1.2114 

.2124 

1.2134 

.2144 

1.2154 

1.2164 

1.2175 

26 

1.2185 

1.2195 

1.2205 

.2216 

.2226 

1.2236 

.2247 

1.2257 

1.2267 

1.2278 

27 

1.2288 

1.2299 

1.2309 

.2319 

.2330 

1.2340 

.2351 

1.2361 

1.2372 

1.2383 

28 

1.2393 

1.2404 

1.2414 

.2425 

.2436 

1.2446 

.2457 

1.2468 

1.2478 

1.2489 

29 

1.2500 

1.2511 

1.2522 

.2532 

.2543 

1.2554 

.2565 

1.2576 

1.2587 

1.2598 

30 

1.2609 

1.2620 

1.2631 

.2642 

1.2653 

1.2664 

.2675 

1.2686 

1.2697 

1.2708 

31 

1.2719 

1.2730 

1.2742 

.2753 

1.2764 

1.2775 

.2787 

1.2798 

1.2809 

1.2821 

32 

1.2832 

1.2843 

1.2855 

.2866 

1.2877 

1.2889 

.2900 

1.2912 

1.2923 

1.2935 

33 

1.2946 

1.2958 

1.2970 

.2981 

1.2993 

1.3004 

1.3016 

1.3028 

1.3040 

1.3051 

34 

1.3063 

1.3075 

1.3087 

.3098 

1.3110 

1.3122 

1.3134 

1.3146 

1.3158 

1.3170 

35 

1.3182 

1.3194 

1.3206 

.3218 

1.3230 

1  3242 

1.3254 

1.3266 

1.3278 

1.3291 

382 


WATERPROOFING  ENGINEERING 


TABLE  XXVIIL— Continued 

f*f\o  r~  1  co   p*/»        -| 

Specific  Gravities  at  — ^  F.         '     C.     Corresponding  to  Degrees  Baum6  for 
60         L15  .55     J 

Liquids  Heavier  than  Water 


Degrees 
Baume. 

TENTHS  OF  DEGREES  BAUME. 

0 

1 

2 

3 

4 

5 

6 

7 

8 

9 

36 

1.3303 

1.3315 

1.3327 

1.3339 

.3352 

1.3364 

1.3376 

1.3389 

1.3401 

1.3414 

37 

1.3426 

.3438 

1.3451 

1.3463 

.3476 

1.3488 

1.3501 

1.3514 

1.3526 

1.3539 

38 

1.3551 

.3564 

1.3577 

1.3590 

.3602 

1.3615 

1.3628 

1.3641 

1.3653 

1.3666 

39 

1.3679 

.3692 

1.3705 

1.3718 

.3731 

1.3744 

.3757 

1.3770 

1.3783 

1.3796 

40 

1.3810 

.3823 

1.3836 

1.3849 

.3862 

1.3876 

.3889 

1.3902 

1.3916 

1.3929 

41 

.3942 

.3956 

1.3969 

1.3983 

.3996 

1.4010 

.4023 

1.4031 

1.4050 

1.4064 

42 

.4078 

.4091 

1.4105 

1.4119 

.4133 

.4146 

.4160 

1.4174 

1.4188 

1.4202 

43 

.4216 

.4230 

1.4244 

1.4258 

1.4272 

.4286 

.4300 

1.4314 

1.4328 

1.4342 

44 

.4356 

1.4371 

1.4385 

1.4399 

1.4414 

.4428 

.4442 

1.4457 

1.4471 

1.4486 

45 

.4500 

1.4515 

1.4529 

1.4544 

1.4558 

.4573 

.4588 

1.4602 

1.4617 

1.4632 

46 

.4646 

1.4661 

1.4676 

1.4691 

1.4706 

.4721 

.4736 

1.4751 

1.4766 

1.4781 

47 

.4796 

1.4811 

1.4826 

1.4841 

1.4857 

.4872 

.4887 

1.4902 

1.4918 

1.4933 

48 

1.4948 

1.4964 

1.4979 

1.4995 

1.5010 

.5026 

.5041 

1.5057 

1  .  5073 

1.5088 

49 

1.5104 

1.5120 

1.5136 

1.5152 

1.5167 

.5183 

.5199 

1.5215 

1.5231 

1.5247 

50 

1.5263 

1.5279 

1.5295 

1.5312 

1.5328 

.5344 

.5360 

1.5376 

1.5393 

1.5409 

51 

1.5426 

1.5442 

1.5458 

1.5475 

1.5491 

.5508 

1.5525 

1.5541 

1.5558 

1.5575 

52 

1.5591 

1.5608 

1.5625 

1.5642 

.5659 

.5676 

1.5693 

1.5710 

1.5727 

1.5744 

53 

1.'5761 

1.5778 

1.5795 

1.5812 

.5830 

.5847 

1.5864 

1.5882 

1.5889 

1.5917 

54 

1.5934 

1.5952 

1.5969 

1.5987 

.6004 

.6022 

1.6040 

1.6058 

1.6075 

1.6093 

•  55 

1.6111 

1.6129 

1.6147 

1.6165 

.6183 

.6201 

1.6219 

1.6237 

1.6256 

1.6274 

56 

1.6292 

1.6310 

1.6329 

1.6347 

.6366 

.6384 

1.6403 

1.6421 

1.6440 

1.6459 

57 

1.6477 

1.6496 

1.6515 

1.6534 

.6553 

.6571- 

1.6590 

1.6609 

1.6628 

1.6648 

58 

1.6667 

1.6686 

1.6705 

1.6724 

.6744 

.6763 

1.6782 

1.6802 

1.6821 

1.6841 

59 

.6860 

1.6880 

1.6900 

1.6919 

.6939 

.6959 

1.6979 

1.6999 

1.7019 

1.7039 

60 

.7059 

1.7079 

1.7099 

1.7119 

.7139 

.7160 

1.7180 

1.7200 

1.7221 

1.7241 

61 

.7262 

1.7282 

1.7303 

1.7324 

.7344 

.7365 

1.7386 

1.7407 

1.7428 

1.7449 

62 

.7470 

1.7491 

1.7512 

1.7533 

.7554 

.7576 

1.7597 

1.7618 

1.7640 

.7661 

63 

.7683 

1.7705 

1.7726 

1.7748 

.7770 

.7791 

1.7813 

1.7835 

1.7857 

.7879 

64 

.7901 

1.7923 

1.7946 

1.7968 

.7990 

.8012 

1.8035 

1.8057 

1.8080 

.8102 

65 

.8125 

1.8148 

1.8170 

1.8193 

.8216 

.8239 

1.8262 

1.8285 

1.8308 

.8331 

66 

.8354 

1.8378 

1.8401 

1.8424 

.8448 

.8471 

1.8495 

1.8519 

1.8542 

.8566 

67 

.8590 

1.8614 

1.8638 

1.8662 

.8686 

.8710 

1.8734 

1.8758 

1.8782 

.8807 

68 

.8831 

1.8856 

1.8880 

1.8905 

.8930 

.8954 

1.8979 

1.9004 

1.9029 

.9054 

69 

.9079 

1.9104 

1.9129 

1.9155 

.9180 

.9205 

1.9231 

1.9256 

1.9282 

1.9308 

70 

.9333 

PRACTICAL  TABLES 


383 


TABLE  XXIX 

60°       ri5°  56     ~\ 
Specific  Gravities  at  —5  F.         '     C.     Corresponding  to  Degrees  Baume  for 

Liquids  Lighter  than  Water 


60° 
Calculated  from  the  formula,  specific  gravity      3F.  = 


140 


~1 
Baum-J 


TENTHS  OF  DEGREES  BAUME. 


A^CfelCCO 

Baume. 

0 

l 

2 

3 

4 

5 

6 

7 

8 

9 

10 

1.0000 

0.9993 

0.9986 

0.9979 

0.9972 

0.9964 

0.9957 

0.9950 

0.9943 

0.9936 

11 

.9929 

.9922 

.9915 

.9908 

.9901 

.9894 

.9887 

.9880 

.9873 

.9866 

12 

.9859 

.9852 

.9845 

.9838 

.9831 

.9825 

.9818 

.9811 

.9804 

.9797 

13 

.9790 

.9783 

.9777 

.9770 

.9763 

.9756 

.9749 

.9743 

.9736 

.9729 

14 

.9722 

.9715 

.9709 

.9702 

.9695 

.9689 

.9682 

.9675 

.9669 

.9662 

15 

.9655 

.9649 

.9642 

.9635 

.9629 

.9622 

.9615 

.9609 

.9602 

.9596 

16 

.9589 

.9582 

.9576 

.9569 

.9563 

.9556 

.9550 

.9543 

.9537 

.9530 

17 

.9524 

.9517 

.9511 

.9504 

.9498 

.9492 

.9485 

.9479 

.9472 

.9466 

18 

.9459 

.9453 

.9447 

.9440 

.9434 

.9428 

.9421 

.9415 

.9409 

.9402 

19 

.9396 

.9390 

.9383 

.9377 

.9371 

.9365 

.9358 

.9352 

.9346 

.9340 

20 

.9333 

.9327 

.9321 

.9315 

.9309 

.9302 

.9296 

.9290 

.9284 

.9278 

21 
22 

.9272 
.9211 

.9265 
.9204 

.9259 
.9198 

.9253 
.9192 

.9247 
.9186 

.9241 
.9180 

.9235 
.9174 

.9229 
.9168 

.9223 
.9162 

.9217 
.9156 

23 

.9150 

.9144 

.9138 

.9132 

.9126 

.9121 

.9115 

.9109 

.9103 

.9097 

24 

.9091 

.9085 

.9079 

.9073 

.9067 

.9061 

.9056 

.9050 

.9044 

.9038 

25 

.9032 

.9026 

.9021 

.9015 

.9009 

.9003 

.8997 

.8992 

.8986 

.8980 

26 

.8974 

.8969 

.8963 

.8957 

.8951 

.8946 

.8950 

.8934 

.8929 

.8923 

27 

.8917 

.8912 

.8906 

.8900 

.8895 

.8889 

.8883 

.8878 

.8872 

.8866 

28 

.8861 

.8855 

.8850 

.8844 

.8838 

.8833 

.8827 

.8822 

.8816 

.8811 

29 

.8805 

.8799 

.8794 

.8788 

.8783 

.8777 

.8772 

.8766 

.8761 

.8755 

30 

.8750 

.8745 

.8739 

.8734 

.8728 

.8723 

.8717 

.8712 

.8706 

.8701 

31 

.8696 

.8690 

.8685 

.8679 

.8674 

.8669 

.8663 

.8658 

.8653 

.8647 

32 

.8642 

.8637 

.8631 

.8626 

.8621 

.8615 

.8610 

.8605 

.8600 

.8594 

33 

.8589 

.8584 

.8578 

.8573 

.8568 

.8563 

.8557 

.8552 

.8547 

.8542 

34 

.8537 

.8531 

.8526 

.8521 

.8516 

.8511 

.8505 

.8500 

.8495 

.8490 

35 

.8485 

.8480 

.8475 

.8469 

.8464 

.8459 

.8454 

.8449 

.8444 

.8439 

36 

.8434 

.8429 

.8424 

.8419 

.8413 

.8408 

.8403 

.8398 

.8393 

.8388 

37 

.8383 

.8378 

.8373 

.8368 

.8363 

.8358 

.8353 

.8348 

.8343 

.8338 

38 

.8333 

.8328 

.8323 

.8318 

.8314 

.8309 

.8304 

.8299 

.8294 

.8289 

39 

.8284 

.8279 

.8274 

.8269 

.8264 

.8260 

.8255 

.8250 

.8245 

.8240 

384 


WATERPROOFING   ENGINEERING 


TABLE  XXIX.—C(mtinued 

Specific  Gravities  at   — -  F.    — i- C.     Corresponding  to  Degrees  Baume*  for 
oU         |_lo.  oo     J 

Liquids  Lighter  than  Water 


Degrees 
Baume. 

TENTHS  OF  DEGREES  BAUME. 

0 

1 

2 

3 

4 

5 

6 

7 

8 

9 

40 

0.8235 

0.8230 

0.8226 

0.8221 

0.8216 

0.8211 

0.8206 

0.8202 

0.8197 

0.8192 

41 

.8187 

.8182 

.8178 

.8173 

.8168 

.8163 

.8159 

.8154 

.8149 

.8144 

42 

.8140 

.8135 

.8130 

.8121 

.8121 

.8116 

.8111 

.8107 

.8102 

.8097 

43 

.8092 

.8088 

.8083 

.8078 

.8074 

.8069 

.8065 

.8060 

.8055 

.8051 

44 

.8046 

.8041 

.8037 

.8032 

.8028 

.8023 

.8018 

.8014 

.8009 

.8005 

45 

.8000 

.7995 

.7991 

.7986 

.7982 

.7977 

.7973 

.7968 

.7964 

.7959 

46 

.7955 

.7950 

.7946 

.7941 

.7937 

.7932 

.7928 

.7923 

.7919 

.7914 

47 

.7910 

.7905 

.7901 

.7896 

.7892 

.7887 

.7883 

.7878 

.7874 

.7870 

48 

.7865 

.7861 

.7858 

.7852 

.7848 

.7843 

.7839 

.7834 

.7830 

.7826 

49 

.7821 

.7817 

.7812 

.7808 

.7804 

.7799 

.7795 

.7791 

.7786 

.7782 

50 

.7778 

.7773 

.7769 

.7765 

.7761 

.7756 

.7752 

.7748 

.7743 

.7739 

51 

.7735 

.7731 

.7726 

.7722 

.7718 

.7713 

.7709 

.7705 

.7701 

.7697 

52 

.7692 

.7688 

.7684 

.7680 

.7675 

.7671 

.7667 

.7663 

.7659 

.7654 

53 

.7650 

.7646 

.7642 

.7638 

.7634 

.7629 

.7625 

.7621 

.7617 

.7613 

54 

.7609 

.7605 

.7600 

.7596 

.7592 

.7588 

.7584 

.7580 

.7576 

.7572 

55 

.7568 

.7563 

.7559 

.7555 

.7551 

.7547 

.7543 

.7539 

.7535 

.7531 

56 

.7527 

.7523 

.7519 

.7515 

.7511 

.7507 

.7503 

.7499 

.7495 

.7491 

57 

.7487 

.7483 

.7479 

.7475 

.7471 

.7467 

.7463 

.7459 

.7455 

.7451 

58 

.7447 

.7443 

.7439 

.7435 

.7431 

.7427 

.7423 

.7419 

.7415 

.7411 

59 

.7407 

.7403 

.7400 

.7393 

.7392 

.7388 

.7384 

.7380 

.7376 

.7372 

60 

.7368 

.7365 

.7361 

.7357 

.7353 

.7349 

.7345 

.7341 

.7338 

.7334 

61 

.7330 

.7326 

.7322 

.7318 

.7315 

.7311 

.7307 

.7303 

.7299 

.7205 

62 

.7292 

.7288 

.7284 

.7280 

.7277 

.7273 

.7269 

.7265 

.7261 

.72/8 

63 

.7254 

.7250 

.7246 

.7243 

.7239 

.7235 

.7231 

.7228 

.7224 

.7220 

64 

.7216 

.7213 

.7209 

.7205 

.7202 

.7198 

.7194 

.7191 

.7187 

.7183 

65 

.7179 

.7176 

.7172 

.7168 

.7165 

.7161 

.7157 

.7154 

.7150 

.7147 

66 

.7143 

.7139 

.7136 

.7132 

.7128 

.7125 

.7121 

.7117 

.7114 

.7110 

67 

.7107 

.7103 

.7099 

.7096 

.7092 

.7089 

.7085 

.7081 

.7078 

.7074 

68 

.7071 

.7067 

.7064 

.7060 

.7056 

.7053 

.7049 

.7046 

.7042 

.7036 

69 

.7035 

.7032  .7028 

.7025 

.7021 

.7018 

.7014 

.7011 

.7007 

.7004 

PRACTICAL  TABLES 


385 


TABLE  XXIX.— Continued 

60°      n^0  'ifi    ~\ 

Specific  Gravities  of  — —  F.    -     '     C.      Corresponding  to  Degrees   Baume  for 

60  |_15.    56       J 

Liquids  Lighter  than  Water 


Degrees 
Baum6. 

TENTHS  OF  DEGREES  BAUME. 

0 

1 

2 

3 

4 

5 

6 

7 

8 

9 

70 

0.7000 

0.6997 

0.6993 

0.6990 

0.6986 

0.6983 

0.6979 

0.6976 

0.6972 

0.6969 

71 

.6965 

.6962 

.6958 

.6955 

.6951 

.6948 

.6944 

.6941 

.6938 

.6934 

72 

.6931 

.6927 

.6924 

,6920 

.6917 

.6914 

.6910 

.6907 

.6903 

.6900 

73 

.6897 

.6893 

.6890 

.6886 

.6883 

.6880 

.6876 

.6873 

.6869 

.6866 

74 

.6863 

.6859 

.6856 

.6853 

.6849 

.6846 

.6843 

.6839 

.6836 

.6833 

75 

.6829 

.6826 

.6823 

.6819 

.6816 

.6813 

.6809 

.6806 

.6803 

.6799 

76 

.6796 

.6793 

.6790 

.6786 

.6783 

.6780 

.6776 

.6773 

.6770 

.6767 

77 

.6763 

.6760 

.6757 

.6753 

.6750 

.6747 

.6744 

.6740 

.6737 

.6734 

78 

.6731 

.6728 

.6724 

.6721 

.6718 

.6715 

.6711 

.6708 

.6705 

.6702 

79 

.6699 

.6695 

.6692 

.6689 

.6686 

.6683 

.6679 

.6676 

.6673 

.6670 

80 

.6667 

.6663 

.6660 

.6657 

.6654 

.6651 

.6648 

.6645 

.6641 

.6638 

81 

.6635 

.6632 

.6629 

.6626 

.6623 

.6619 

.6616 

.6613 

.6610 

.6607 

82 

.6604 

.6601 

.6598 

.6594 

.6591 

.6588 

.6585 

.6582 

.6579 

.6576 

83 

.6573 

.6570 

.6567 

.6564 

.6560 

.6557 

.6554 

.6551 

.6548 

.6545 

84 

.6542 

.6539 

.6536 

.6533 

.6530 

.6527 

.6524 

.6521 

.6518 

.6515 

85 

.6512 

.6509 

.6506 

.6503 

.6500 

.6497 

.6494 

.6490 

.6487 

.6484 

86 

.6482 

.6479 

.6476 

.6473 

.6470 

.6467 

.6464 

.6461 

.6458 

.6455 

87 

.6452 

.6449 

.6446 

.6443 

.6440 

.6437 

.6434 

.6431 

.6428 

.6425 

88 

.6422 

.6419 

.6416 

.6413 

.6410 

.6407 

.6404 

.6401 

.6399 

.6396 

89 

.6393 

.6390 

.6387 

.6384 

.6381 

.6378 

.6375 

.6372 

.6369 

.6367 

90 

.6364 

.6361 

.6358 

.6355 

.6352 

.6349 

.6346 

.6343 

.6341 

.6338 

91 

.6335 

.6332 

.6329 

.6326 

.6323 

.6321 

.6318 

.6315 

.6312 

.6309 

92 

.6306 

.6303 

.6301 

.6298 

.6295 

.6292 

.6289 

.6286 

.6284 

.6281 

93 

.6278 

.6275 

.6272 

.6270 

.6267 

.6264 

.6261 

.6258 

.6256 

.6253 

94 

.6250 

.6247 

.6244 

.6242 

.6239 

.6236 

.6233 

.6231 

.6228 

.6225 

95 

.6222 

.6219 

.6217 

.6214 

.6211 

.6208 

.6206 

.6203 

.6200 

.£197 

96 

.6195 

.6192 

.6189 

.6186 

.6184 

.6181 

.6178 

.6176 

.6173 

.6170 

97 

.6167 

.6165 

.6162 

.6159 

.6157 

.6154 

.6151 

.6148 

.6146 

.6143 

98 

.6140 

.6138 

.6135 

.6132 

.6130 

.6127 

.6124 

.6122 

.6119 

.6116 

99 

.6114 

.6111 

.6108 

.6106 

.6103 

.6100 

.6098 

.6095 

.6092 

.6090 

100 

.6087 

* 

386  WATERPROOFING  ENGINEERING 

asphalt  binder  is  to  be  used  instead  the  weight  of  the  membrane 
may  be  taken  as  15  per  cent  less  than  the  values  given  in  the  table. 

The  weights  and  thicknesses  noted  in  columns  3,  4  and  5,  are 
average  values  of  many  specimens  actually  weighed  and  measured. 
The  rest  of  the  items  were  calculated.  The  two  thicknesses  of  binder 
film,  Y&  mcn  and  ^-inch  were  assumed  because  r^-inch  is  the  thick- 
ness of  a  film  of  binder  when  carefully  applied  with  a  single  mopping, 
while  the  ^-inch  film  is  obtained  with  a  double  mopping  which  is 
sometimes  called  for  on  important  work.  Where  the  ^-inch  thick- 
ness of  film  is  used  only  half  the  number  of  plies  required  for  the 
YQ  inch  would  be  necessary  under  the  same  conditions  of  water 
pressure,  etc. 

While  jute  burlap  weighing  7,  8,  9,  10  and  even  11  ounces  is  some- 
times used,  the  7J-ounce  open-mesh  variety  is  most  extensively 
used.  No.  26  felt  is  a  very  commonly  used  grade,  though  anywhere 
from  No.  20  to  No.  50  felts  are  used  for  membrane  waterproofing. 
The  heavier-weight  felts  are  usually  used  for  roofing.  The  medium- 
weight  cotton  fabrics  are  most  extensively  used  for  membrane  water- 
proofing. These  weights  range  from  4  to  6  ounces  per  square  yard. 

For  obtaining  weights  of  complete  membranes  consisting  of  more 
than  6  plies,  the  simplest  way  is  to  draw  a  curve  on  cross-section 
paper  for  three  or  four  values  in  which  the  number  of  plies  are  the 
abscissa  and  the  weights  are  the  ordinates.  It  will  be  found  that 
the  curves  so  drawn  are  straight  lines  and  may  be  produced  to  give 
the  values  sought. 

Table  XXXII,  "  Thickness  of  Waterproofing  Materials  for  Dif- 
ferent Water  Pressures,"  shows  the  approximate  number  of  felt  and 
fabric  plies,  thicknesses  of  mortar  and  mastic  layers  and  the  number 
of  courses  of  various  kinds  of  waterproofing  materials  (applicable 
to  the  membrane  or  surface-coating  types  of  waterproofing),  required 
under  various  heads  of  water.  It  is  compiled  from  a  careful  study 
of  the  general  field  practice  in  waterproofing  underground  structures. 
The  bituminous  sheet  mastic  layers,  the  brick-in-mastic  courses  and 
the  different  membranes,  should  be  protected,  or  rather,  encased 
in  masonry,  both  to  support  them  and  protect  them  from  climatic 
temperature  changes.  The  surface-mortar  coats,  J  inch  thick  or 
less,  must  not  be  put  on  in  several  layers  to  make  up  there  quired 
thickness,  but  the  thicker  mortar  coats  may  have  a  scratch  coat, 
and  together  with  the  "  finish  coat "  should  make  up  the  required 
thickness.  Both  the  thin  and  thick  mortar  coats  must  be  applied 
continuously  over  or  on  the  structure  until  completed. 

Table  XXXIII,  "  Volumes  and  Weights  of  Ingredients  used  in 


PRACTICAL  TABLES 


387 


Brick-in-  (Asphalt)  Mastic  Waterproofing/'  is  based  on  present- 
day  practice  of  laying  common  bricks  in  a  bituminous  mastic  to 
form  a  thick  waterproofing  envelope  about  an  underground  structure. 
It  is  further  based  on  the  use  of  asphalt  only  for  making  the  mastic, 
but  coal-tar  pitch  can  be  used  with  practically  equally  good  results. 
The  weight  of  asphalt  was  assumed  to  be  66  pounds  per  cubic  foot. 
The  average  weight  of  coal-tar  pitch  is  76  pounds  per  cubic  foot. 

The  size  of  joints  between  bricks  in  the  brick-in-mastie  envelope 
is  of  vital  importance.  Bricks  laid  close  together,  that  is,  without 
joints,  vitiate  the  function  of  the  waterproofing  envelope.  It  is 
obvious  that  the  bricks  do  not  constitute  a  waterproofing  medium 

TABLE  XXX.— SPECIFIC  GRAVITY  AND  COEFFICIENT  OF  EXPAN- 
SION  OF  VARIOUS   MATERIALS 


Substance. 

Specific 
Gravity 
at  62°  F. 
(Aver.). 

Volu- 
metric 
Coeffici- 
ent of 
Expan- 
sion Per 
Deg.  F. 
(Aver.). 

Substance. 

Specific 
Gravity 
at  62°  F. 
(Aver.). 

Lineal 
Coeffici- 
ent of 
Expan- 
sion 
Per  Deg. 
F. 
(Aver.). 

Alcohol  (100%) 

0  79 

.  00058 

Asbestos  

2.81 

Asphalt,  artificial  (Eastern 

Brick  (common)  
Brick  masonry  

1.922 
2.00 

.  00000306 
.  0000031 

21°  Baume  
Asphalt,  Bermudez  Lake.   . 
Asphalt,  Mexican  
Asphalt       Trinidad      Lake 

1.3 

1.061 
1.0361 

.000507 
.  000352 
.  00028S* 

Cedar  
Clay  ''Dry  lumps)  
CoL.._ete  (stone)  
Copper  

0.45 
1.80 
2.33 

8.88 

.  0000068 
.  0000093 

1  21 

000352 

Glass      .               

3.1 

.0000041 

Asphalt,  Trinidad,  liquid.  . 
Beeswax  

0.96 
0.955 
0  96 

.  000303 
.000150 

Granite  (New  Hamp.). 
Graphite  
Gypsum       

2.66 
2.26 
2.27 

.  0000047 
.  0000044 

China  wood  oil     
Caoutchouc  (rubber) 

0.944 
0.94 
1  07 

.  000355 

Hydrated  lime  
Iron  (wrought)      
Lead  

2.12 
7.70 
11.40 

.  0000067 
.0000159 

Fats 

0  935 

Lime  (slaked)    

1.35 

Gutta  Percha  
Ice 

0.99 
0  92 

.000332 
00004088 

Limestone  
Marble 

2.72 
2  65 

.0000045 
0000056 

0  927 

0003  807 

Mortar  (1  •  2) 

1  84 

00000561 

Paraffin  (hard) 

0  908 

000568 

Oak  (white)  .... 

0  77 

0000027 

Oils  (vegetable) 

0  925 

Pine  (long  leaf)  

0.61 

.  0000030 

Oils  (mineral)    
Petroleum,      Mexican     as- 
phaltic  (crude)  

0.915 

0.878 
1  298 

.  000392 
0002435 

Plaster  (white)    
Portland  cement  (set)  .  .  . 
Rubble  masonry  

'2^95' 
2.48 
2  44 

.  0000092 
.0000067 
.  0000035 
0000061 

Pitch   oil  tar 

1  218 

0002586 

Slate    

2.81 

.  0000058 

1   1 

Steel     

7.80 

.0000061 

Rubber  (sheet) 

1  5 

Terra  Cotta  

1.9 

Tallow 

0  94 

Tiles     

2.20 

0  860 

0004547 

Tin  (rolled)     

7.40 

.0000117 

Water  (4°  C  ) 

1  000 

000086 

Zinc  (rolled)  .             .... 

7.05 

.  000017 

Wax  

0.965 

1  Specific  gravity  at  77  deg.  Fahr. 

2  Asphalt  having  penetration  between  0.50  and  0.75  cm.  at  77  deg.  Fahr.  (100  grams,  '. 
seconds).     Coefficient  between  77  and  300  deg.  Fahr. 

3  Asphalt  is  for  cold  application.     Coefficient  between  77  and  100  deg.  Fahr. 

4  Asphalt  having  penetration  between  0.65  and  0.83  cm.  at  77  deg.  Fahr. 

6  Straight-run  product  having  a  melting-point  of  137  deg.  Fahr.  by  the  cube-in-water 
method.  Coefficient  between  60  and  180  deg.  Fahr. 

6  Melting  point  160  deg.  Fahr.  by  the  cube-in-water  method.  Coefficient  between  60 
and  180  deg.  Fahr. 

»  Between  50  deg.  and  100  deg.  Fahr. 

«  At  +  30  deg.  Fahr.,  reducing  to  .0000197  at  -  30  deg.  Fahr. 


388 


WATERPROOFING  ENGINEERING 


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PRACTICAL  TABLES 


389 


in  themselves,  they  merely  furnish  "  body,"  depth  and  weight  to 
the  envelope  and  economy  in  the  waterproofing  system.  The  bitu- 
minous mastic  alone  is  the  waterproofing  medium,  hence  the  more 
of  it  present — within  economical  limits,  of  course — the  better.  The 
smallest  joint  should  be  not  less  than  f  inch  and  the  largest  need 
not  be  more  than  J  inch.  Therefore  the  volume  and  weight  of  the 
various  ingredients  have  been  calculated  on  this  basis;  also  on  the 
empirical  basis  of  a  20  per  cent  and  30  per  cent  reduction  in  volume 
of  mastic,  as  compared  to  volume  of  ingredients  (see  Chapter  VII), 
mixed  in  proportions  of  2  :  1  :  1  and  1  :  1  :  1,  respectively. 

TABLE    XXXII.— THICKNESS    OF    WATERPROOFING    MATERIALS 
REQUIRED   FOR   DIFFERENT   WATER   PRESSURES 


NUMBER  OF  PLIES,  LAYERS  OR  COURSES. 

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*  Each  third  ply  to  be  either  jute  or  cotton  fabric. 

t  Sheet  mastic  composed  of  15  to  25  per  cent  of  bitumen;  sand,  grit  and  cement  or  lime- 
stone dust  in  equal  proportions. 

t  Mastic  (for  brick  and  mastic)  composed  of  35  to  45  per  cent  of  bitumen,  and  equal  parts 
of  sand  and  cement,  or  limestone  dust. 

(a)   Open-mesh  variety. 

(6)   Closed-mesh  variety. 

(c)  Bricks  laid  on  8  X3£  inch  face,  on  horizontal  and  against  vertical  surfaces. 

(rf)  Bricks  laid  on  8X2£  inch  face,  on  horizontal  surfaces,  but  on  the  3Hnch  face  against 
vertical  surfaces. 


390 


WATERPROOFING  ENGINEERING 


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392 


WATERPROOFING  ENGINEERING 


Table  XXXIV,  "  Pressure  Exerted  by  Water  Beneath  Floors 
and  Against  Walls,"  is  based  on  the  principles  of  hydrostatic  pres- 
sure, which  are,  (1)  the  pressure  on  the  base  of  a  vessel  containing 
water  is  equal  to  the  height  of  water  above  the  base,  times  its  area; 
(2)  the  average  water  pressure  on  the  side  of  a  vessel  is  equal  to 
one-half  the  height  of  the  water  in  the  vessel,  times  the  area  of  the 
vertical  surface  in  contact  with  the  water;  (3)  the  pressure  of  water 
is  transmitted  equally  in  all  directions.  The  type  of  waterproofing 
is  often  governed  by  the  water  pressure  it  will  have  to  resist  as  judged 
by  the  height  of  ground  or  mean  high  water  level  above  the  base  of 
the  structure  to  be  waterproofed.  The  table  converts  this  height 
into  pounds  pressure  for  each  of  the  above  three  conditions. 


TABLE  XXXIV.— PRESSURE  EXERTED   BY  WATER  BENEATH 
FLOORS  AND   AGAINST  WALLS 


Hydrostatic  Head— 
Feet. 

Pressure 
per  Square  Inch  — 
Lbs. 

Lifting  Pressure 
per  Square  Foot 
(Under   Floor)—  Lbs. 

Average  Pressure 
per  Square  Foot  on  Wall 
Surface  Affected.  —  Lbs. 

0.5 

0.21 

31.2 

15.6 

1.0 

0.43 

62.5 

31.2 

2.J 

0.86 

125.0 

62.5 

3.0 

1.30 

187.5 

93.7 

4.0 

1.73 

250.0 

125.0 

5.0 

2.17 

312.5 

156.2 

6.0 

2.60 

375.0 

187.5 

8.0 

3.47 

500.0 

250.0 

10.0 

4.34 

625.0 

312.5 

12.0 

5.21 

750.0 

375.0 

15.0 

6.51 

937.5 

468.7 

20.0 

8.68 

1250.0 

625.0 

25.0 

10.85 

1562.5 

781.2 

30.0 

13.02 

1875.0 

937.5 

40.0 

17.36 

2500.0 

1250.0 

60.0 

26.04 

3750.0 

1875.0 

80.0 

34.72 

5000.0 

2500.0 

100.0 

43.40 

6250.0 

3125.0 

Table  XXXV,  "  Approximate  Weight  and  Thickness  of  Various 
Sheet  Metals  for  Roofings,  Gutters  and  Flashings,"  gives  the  weight, 
thickness  and  gauge  number  of  various  sheet  metals  commonly  used 
for  gutters,  flashings,  and  roofings.  Sheet  metal  is  usually  designated 
by  the  weight  of  a  superficial  foot,  in  pounds  or  ounces,  or  by  some 
standard  gauge.  All  tin,  iron  and  steel  are  figured  on  the  U.  S. 
Standard  gauge;  copper  is  figured  on  the  Brown  &  Sharpe  gauge; 


PRACTICAL  TABLES 


393 


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PRACTICAL  TABLES 


395 


zinc  has  a  gauge  of  its  own,  while  lead  is  usually  figured  at  so  many 
pounds  to  the  square  foot,  such  as  2-pound  lead,  3-pound  lead,  etc. 
Galvanized  sheets  have  a  gauge  based  on  their  weights,  and  not  on 
the  thickness.  Corrugated  galvanized  sheets  usually  figured  on 
the  U.  S.  Standard  gauge,  are  made  in  standard  widths  of  corru- 
gations, and  in  standard  lengths,  ranging  from  5  to  10  feet,  with 
a  maximum  length  of  12  feet. 

Table  XXXVI,  "Weights  of  Roof  Coverings,"  gives  closely 
approximate  weights  of  various  roof  coverings  and  sheathings. 
These  figures  are  very  useful  for  designing  and  estimating. 

TABLE  XXXVI.— WEIGHTS   OF  ROOF  COVERINGS 


Material. 


Average  Weight  in 

Lbs.  per  Sq.  Ft 

of  Roof. 


Ash  wood  sheathing,  1-in.  thick 5.0 

Asbestos  shingles  (laid  French  method) 2.8 

Asbestos  shingles  (laid  American  method) 4.0 

Chestnut  wood  sheathing,  1-in.  thick 4.0 

Copper,  16  oz.,  standing  seam 1.3 

Clay  tiles  (plain)  10£  by  6i  by  f  ins.,  5£  in.  to  the  weather.  . .  18.0 

Clay  tiles  (Spanish)  14£  by  10£  ins.,  7i  ins.  to  the  weather.  .  .  8.5 

Felt  and  asphalt  (3  plies)  (without  sheathing) 2.0 

Felt,  asphalt  and  gravel  (6  plies)  (without  sheathing) 8.0-10.0 

Glass,  i-in.  thick 1.8 

Hemlock  sheathing,  1-in.  thick 2.0 

Iron,  corrugated,  No.  16,  B.W.G.  (without  sheathing)       3.6 

Iron,  galvanized,  flat  No.  16,  B.W.G.  (without  sheathing) ....  3.0 

Maple  sheathing,  1-in.  thick 4.0 

Oak  sheathing,  1-in.  thick 5.0 

Sheet  iron,  ^g-in.  thick  3.0 

Sheet-lead,  about  i-in.  thick 8.0 

Slag  roofing  (four-ply) 4.0 

Slate,  |-in.  thick 9.0 

Slate,  fk-in.  thick  (double-lap) 6.8 

Slate,  |-in.  thick  (3  in.  double-lap) 4.5 

Spruce  sheathing,  1-in.  thick 2.5 

Terne  plate  (tin),  1C  (without  sheathing) 0.5 

Terne  plate  (tin),  IX  (without  sheathing) 0.7 

Tiles,  2  in.  to  4  in.  thick  (plain,  with  mortar) 15.0 

White  pine  sheathing,  1-in.  thick 2.5 

Wood  shingles,  6  by  18  ins.,  |  to  the  weather 2.0 

Yellow  pine  sheathing,  1-in.  thick 4.0 

Zinc  No.  20,  B.W.G 1.5 


WATERPROOFING  ENGINEERING 


Table  XXXVII,  "Square  Feet  Covered  by  1000  Wooden 
Shingles,"  gives  the  covering  capacity  of  a  thousand  wooden  shingles 
of  various  lengths  and  widths,  according  to  fractions  exposed  to  the 
weather.  The  number  of  shingles  per  100  square  feet  of  roof  surface 
can  be  easily  calculated  therefrom.  In  doing  so  about  5  per  Cent 
should  be  added  for  hip  roofs  and  about  10  per  cent  for  irregular 
roofs  with  dormer  windows.  The  number  of  nails  required  is  usually 
about  three  times  the  number  of  shingles. 

Table  XXXVIII,  "  Number  of  Slates  and  Pounds  of  Nails  for 
Roofing,"  gives  the  number  of  slate  shingles  and  quantity  of  nails 
required  to  cover  100  square  feet  of  roof  surface.  These  values  are 
also  applicable  to  flat,  baked-clay  tiles. 

Table  XXXIX,  "Size,  Length,  Gauge  and  Weight  of  Roofing 
Nails,"  will  prove  helpful  to  the  roofer.  Nails  shorter  than  J  inch 
are  generally  not  used.  Nails  with  large  flat  heads  and  barbed  shanks 
are  best  for  all  roofing  purposes. 

TABLE   XXXVIL— SQUARE   FEET   COVERED   BY  ONE   THOUSAND 
WOODEN  SHINGLES 


O  ^ 

II 

W 

LENGTH  IN  INCHES. 

16 

18 

20 

24 

Width  in  Inches. 

Width  in  Inches. 

Width 
Inches. 

Width  in  Inches. 

4 

5 

6 

4 

5 

6 

6 

5 

6 

7 

3 

77 

98 

119 

3a 

90 

114 

139 

4 

103 

130 

159 

41 

116 

146 

179 

5 

129 

162 

199 

129 

162 

199 

5| 

142 

178 

219 

142 

178 

219 

6 

155 

194 

,239 

155 

194 

239 

239 

6£ 

.... 

.... 

168 

210 

259 

259 

7 

.... 

181 

226 

279 

279 

226 

279 

329 

8 
81 
9 
91 
10 
10| 
11 

1H 

12 

..'.  . 

194 
207 

242 

258 

299 
319 

299 
319 
339 
359 

242 
258 
274 
290 
306 
322 
338 
354 
370 
386 

299 
319 
339 
359 
379 
399 
419 
439 
459 
479 

353 
377 
401 
425 
449 
473 
479 
521 
545 
569 

PRACTICAL  TABLES 


397 


TABLE  XXXVIIL— NUMBER  OF  SLATES  AND  POUNDS  OF  NAILS 
REQUIRED  FOR  ROOFING  * 

(PER  100  SQ.  FT.) 


Size  of 
Slates 
(Inches). 

No.  of  Inches 
Exposed 
When  Laid. 

No.  per 
Square 
(100  Sq.  Ft.). 

Weight  of 
Galvanized  Nails 
per  Square. 

Lb.         Oz.           d. 

14X24 

10| 

98 

164 

12X24 

10i 

115 

1         10        4 

12X22 

9£ 

126 

1         12        4 

11X22 

9£ 

138 

1         15        4 

12X20 

8£ 

142 

204 

10X20 

8^ 

170 

264 

12X18 

7^ 

160 

1         13        3 

10X18 

U 

192 

233 

9X18 

71 

214 

273 

12X16 

61 

185 

223 

10X16 

6£ 

222 

283 

9X16 

6| 

247 

303 

8.X16 

6£ 

277 

32        3 

10X14 

5£ 

262 

303 

8X14 

51 

328 

3        12        3 

7X14 

5£ 

374 

443 

8X12 

4i 

400 

4          93 

7X12 

4i 

458 

533 

6X12 

^ 

533 

6          1        3 

*  American  Civil  Engineers'  Pocket  Book,  p.  404  (2d  Edition). 

TABLE  XXXIX.— SIZE,  LENGTH,  GAUGE  AND  WEIGHT  OF  ROOFING 

NAILS* 


SLATING  NAILS. 

SHINGLE  NAILS. 

FELT  ROOFING  NAILS, 
LARGE  HEAD, 
BARBED. 

ROOFING  NAILS, 
BARBED. 

d 

d 

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*  As  manufactured  by  Pittsburgh  Steel  Co. 


APPENDICES 


APPENDIX  I 

EXPLANATION    OF    MECHANICAL    ANALYSIS*    FOR    GRADING 
CONCRETE    AGGREGATES 

MECHANICAL  analysis  consists  in  separating  the  particles  or  grains 
of  a  sample  of  any  material,  such  as  broken  stone,  gravel,  sand  or 
cement,  into  the  various  sizes  of  which  it  is  composed,  so  that  the 
material  may  be  represented  by  a  curve  (see  Figs.  139-140),  each 
of  whose  ordinates  is  the  percentage  of  the  weight  of  the  total  sample 
which  passes  a  sieve  having  holes  of  a  diameter  represented  by  the 
distance  of  this  ordinate  from  the  origin  in  the  diagram. 

The  objects  of  mechanical  analysis  curves  as  applied  to  concrete 
aggregates  are  (1)  to  show  graphically  the  sizes  and  relative  sizes 
of  the  particles;  (2)  to  indicate  what  sized  particles  are  needed  to 
make  the  aggregate  more  nearly  perfect  and  so  enable  the  engineer 
to  improve  it  by  the  addition  or  substitution  of  another  material; 
and  (3)  to  afford  means  for  determining  best  proportions  of  differ- 
ent aggregates. 

To  determine  the  relative  sizes  of  the  particles  or  grains  of  which 
a  given  sample  of  stone  or  sand  is  composed,  the  different  sizes  are 
separated  from  each  other  by  screening  the  material  through  succes- 
sive sieves  of  increasing  fineness.  After  sieving,  the  residue  on  each 
sieve  is  carefully  weighed,  and  beginning  with  that  which  has  passed 
the  finest  sieve,  the  weights  are  successively  added,  so  that  each 
sum  will  represent  the  total  weight  of  the  particles  which  have  passed 
through  a  certain  sieve.  The  sums  thus  obtained  are  expressed  as 
percentages  of  the  total  weight  of  the  sample  and  plotted  upon  a 
diagram  with  diameters  of  the  particles  as  abscissae  and  percentages 
as  crdinates. 

A  convenient  outfit  for  such  a  mechanical  analysis  as  above 
described,  consists  of  a  set  of  sieves,  an  apparatus  for  shaking  the 
sieves,  and  scales  for  weighing.  A  standard  size  of  sieve  is  8  inches 
in  diameter  and  2J  inches  high.  Sieves  with  openings  exceeding 
0.10  inch  are  preferably  made  of  spun  hard  brass  with  circular 
*  Taylor  and  Thompson  "  Concrete,  Plain  and  Reinforced,"  p.  193. 

399 


400 


APPENDIX  I 


openings  drilled  to  the  exact  dimensions  required.  Sieves  with  open- 
ings of  0. 10  inch  and  less  are  preferably  of  woven  brass  wire  set  into 
a  hard  brass  frame.  Woven  brass  sieves  are  made  for  many  purposes, 
and  are  sold  by  numbers  which  are  approximately  the  number  of 
meshes  to  the  linear  inch.  As  the  actual  diameter  of  the  hole  varies 
with  the  gauge  of  wire  used  by  different  manufacturers,  every  set  of 
sieves  must  be  separately  calibrated. 

The  number  and  sizes  of  sieves  to  be  used  depends  upon  the  im- 
portance of  the  testing  to  be  done.  A  convenient  set  of  sieves  for 
ordinary  laboratory  practice  is  given  below  in  Table  XL. 

TABLE  XL.— SIZES  OF  SAND  AND  STONE  SIEVES 


Stone  Sieves,  Diameter 
of  Hole  (Inches). 

SAND  SIEVES. 

Commercial  No. 

Diameter  in  Inches. 

Hole. 

Wire. 

3  00 
2.50 

1  in.  round 
No.    7 

0.032 

0.111 

2.00 

"     12 

0.056 

0.027 

1.50 

"    20 

0.0335 

0.0165 

1.00 

"    30 

0.0198 

0.0135 

0.75 

"    50 

0.0120 

0.0080 

0.50 

"    90 

0.0059 

0.0052 

0.25 

"  200 

0.0029 

0.0021 

When  many  analyses  are  to  be  made,  it  is  convenient  to  have  a 
printed  cross-section  form,  with  appropriate  spaces  for  filling  in  the 
number  of  the  analysis,  description  of  the  material,  location  of  the 
work,  and  other  facts  relating  to  the  material. 

For  those  who  are  unfamiliar  with  mechanical  analysis,  a  detailed 
explanation  of  the  method  of  locating  the  curve  is  here  given.  The 
method  can  best  be  understood  by  referring  to  the  diagrams  of 
typical  materials  which  are  also  of  practical  interest  as  illustrating 
the  curves  which  may  be  expected  in  special  cases. 

Fig.  139  represents  a  typical  mechanical  analysis  of  crusher-run 
micaceous  quartz  stone  which  has  been  run  through  a  J-inch  revolv- 
ing screen  so  as  to  separate  particles  finer  than  \  inch,  that  is,  the 
dust  for  use  with  sand. 

For  a  sample  of  stone,  which  may  be  taken  by  the  method  of 
quartering  *  1000  grams  is  a  convenient  quantity  for  8-inch  diameter 

*  The  method  of  quartering  consists  in  taking  shovelfuls  of  the  material 
from  various  parts  of  the  pile,  mixed  together  and  spread  in  a  circle.  The  circle 
is  quartered,  as  one  would  quarter  a  pie;  two  of  the  opposite  quarters  are  shoveled 


GRADING  CONCRETE  AGGREGATES 


401 


sieves  2J  inches  in  depth,  and  also  permits  of  easy  reduction  from 
weights  to  percentages.  To  obtain  the  analysis  shown  in  Fig.  139, 
the  sample  of  stone  is  placed  in  the  upper  (coarsest)  sieve  of  the  nest 
of  stone  sieves  given  in  Table  XL,  and  after  1000  *  shakes  the  nest 
is  taken  apart,  and  the  quantity  caught  on  each  sieve  is  weighed, 
beginning  with  the  finest  and  placing  each  successive  residue  on 
the  scale  pan  with  that  already  weighed.  The  results  obtained  in 
the  particular  case  under  consideration  are  illustrated  in  Table 
LXI,  which  shows  the  method  of  finding  the  percentages: 


55  o3 
-- 


ven  Diameter 

s  i 

2  2  o     3        o            o'                  -<                             -H 

PARTICLES  BELOW  K  INCH 
SIEVED  OUT   FOR  USE 
AS  SAND 

\ 

X 

f 

lx 

/ 

x 

s 

/ 

ercent,  by  Weight,  Smaller  than  gi 

8  §  J 

/ 

X 

,J, 

,-v' 

X 

' 

•  A 

V 

X 

v,  " 

/ 

^ 

x 

.tea 

X 

I 

X 

C 

S 

X 

/ 

^ 

^ 

— 

-* 

0.25 


0.50 


0.75  1.00  1.25 

Diameters  of  Stone  in  Inches 


1.50 


1.75 


2.00 


FIG.    139. — Typical    Mechanical    Analysis    Curve    of    Crusher-run    Micaceous 

Quartz  Stone. 

The  various  percentages  are  plotted  on  the  diagram  and  the  curve 
drawn  through  the  points.  The  vertical  distance  from  the  bottom 
of  the  diagram  to  the  curve,  that  is,  the  ordinate  at  any  point, 
represents  the  percentage  of  the  material  which  passed  through  a 
single  sieve  having  holes  of  the  diameter  represented  by  this  particu- 
lar ordinate.  Since  the  percentage  of  material  passing  any  sieve 
is  always  the  complement  of  the  percentage  of  grains  coarser  than 
that  sieve,  the  vertical  distances  from  the  top  of  the  diagram  down  to 
the  curve  represents  the  percentages  which  would  be  retained 

away  from  the  rest,  thoroughly  mixed,  spread,  and  quartered  as  before.  The 
operation  is  repeated  until  the  quantity  is  reduced  to  that  required  for  the 
sample. 

*  In  practice  to-day  the  custom  prevails  of  shaking  the  material  until  no 
more  comes  through  as  determined  by  successive  weighings. 


402 


APPENDIX  I 


upon  each  sieve  if  employed  alone.  For  example,  taking  1.25,  62 
per  cent,  the  distance  from  the  bottom  of  the  diagram,  represents 
the  percentage  of  material  finer  than  IJ-inch  diameter,  and  38  per  cent, 
the  distance  down  from  the  top  of  diagram,  represents  the  percent- 
age coarser  than  1J  inch. 

TABLE  XLL— RESULTS  OF  SCREENING  SAMPLES  OF  STONE  OF 

FIG.   140 


Size  Sieve. 

Amount  Finer  than 
Each  Sieve. 

Percentage  Finer 
than  Each  Sieve. 

Inches 

Grams 

Per  Cent 

1.50 

801 

80 

1.00 

457 

46 

0.67 

222 

22 

0.45 

99 

10 

0.30 

27 

3 

0.20 

19 

2 

0.15 

8 

1 

0.10 

0 

Typical  curves  of  a  fine,  a  medium  well  graded,  and  a  coarse  sand 
are  shown  in  Fig.  140.     For  convenience  in  plotting,  the  horizontal 


0.025 


0.050 


0.075  0.100  0.125 

Diameters  of  Sand  in  Inches 


0.150 


0.175 


0.200 


FIG.  140.— Typical  Mechanical  Analyses  Curves  of  Fine,  Medium,  Well-graded, 

and  Coarse  Sands. 

scale  is  ten  times  greater  than  that  of  Fig.  139,  the  diagram  showing 
diameters  ranging  from  0  to  0.200  inch  diameter. 

The  mechanical  analysis  of  crusher  dust  is  apt  to  vary  between 
the  curves  of  fine  sand  and  medium  sand  which  are  shown  in  Fig.  140. 


APPENDIX  II 
CONCRETE  IN   SEA  WATER* 

REGARDING  the  chemical  action  of  sea  water  on  concrete  and  its 
prevention,  the  following  information  and  conclusions  are  presented 
here  because  of  their  bearing  on  and  corroboration  of  the  subject 
matter  of  Chapter  I.f 

Investigations  concerning  the  effect  of  sea  water  on  concrete 
immersed  for  periods  up  to  fifty  years  or  more;  of  the  relative  merits 
of  standard  Portland  cement  and  Portland  cement  made  with  dif- 
ferent proportions  of  its  principal  constituents,  in  resisting  the  dis- 
integrating effect  of  sea  water;  of  the  effect  of  varying  the  propor- 
tions of  cement  in  the  mortar  and  concrete;  of  differently  graded 
aggregates;  of  the  addition  of  various  finely  ground  materials  to 
the  cement  after  burning;  of  the  relative  durability  of  concrete 
cast  in  place  as  compared  with  concrete  blocks  allowed  to  harden 
before  placing  in  the  sea ;  and  of  the  effect  of  various  materials  added 
to  the  concrete  mixture  to  produce  impermeability  and  consequent 
increased  durability,  have  been  made  in  European  countries  and  in 
America. 

Regarding  the  chemical  action  of  sea  water  on  cement,  the  fol- 
lowing conclusions  are  presented: 

Cement  containing  up  to  2J  per  cent  of  sulphuric  anhydride 
(SOs)  resists  the  action  of  sea  water  fully  as  well  as  cement  with  lower 
sulphuric  anhydride  content. 

While  all  the  hydraulic  cements  now  in  use  are  liable  to  decomposi- 
tion in  sea  water,  Portland  cement  is  the  one  to  be  preferred  in  every 
respect. 

High  iron  Portland  cement  and  puzzolan  cement  have  failed  to 
show  superiority  over  standard  Portland  cement  in  resisting  the 
disintegrating  effect  of  sea  water. 

*  American  Railway  Engineering  Association,  Vol.  15,  March,  1914,  p.  564. 

t  For  a  presentation  of  practical  results  of  marine  construction  and  valuable 
conclusions  drawn  from  observed  effects  of  sea  water  on  concrete  all  over  the 
United  States,  see  five  articles  by  Rudolph  J.  Wig  and  Lewis  R.  Ferguson  in 
Engineering  News-Record,  commencing  Vol.  79,  No.  12,  1917. 

403 


404  APPENDIX  II 

Regarding  the  effect  of  varying  the  proportions  of  cement  in  the 
mortar  and  concrete,  in  general,  the  richer  mixtures  have  been  found 
to  offer  better  resistance  to  the  attack  of  sea  water.  Proportions 
recommended  for  mortars  are  those  with  one  part  cement  to  one  part 
of  sand  up  to  one  part  cement  to  two  parts  sand.  The  bad  condi- 
tion of  mortars  leaner  than  the  above  after  exposure  in  sea  water, 
stands  out  prominently. 

In  the  use  of  reinforced  concrete  for  maritime  works,  it  is  advis- 
able to  employ  larger  proportions  of  cement  than  are  usual  for  similar 
works  in  fresh  water. 

Concerning  the  addition  of  finely  ground  material  to  the  cement 
after  burning,  it  has  been  found  that  the  addition  of  ground  puzzolan 
or  furnace  slag  to  Portland  cement  increases  the  resistance  of  the 
resulting  mortar  or  concrete  to  the  disintegrating  effect  of  sea  water. 

Regarding  the  use  of  any  material  added  to  the  concrete  mix- 
ture in  small  quantities  in  order  to  reduce  permeability,  no  results 
of  practical  working  tests  have  demonstrated  that  the  effect  of  any 
material  in  reducing  permeability  is  other  than  mechanical,  i.e., 
to  supply  a  deficiency  in  fine  material  in  a  poorly  graded  concrete 
mixture. 

Allowing  the  concrete  to  harden  under  favorable  conditions  before 
exposure  to  the  action  of  sea  water  greatly  increases  its  resistance  to 
attack  by  the  sea  water  and  is  recommended  wherever  possible. 

When  concrete  is  deposited  under  sea  water,  such  precaution 
should  be  observed  as  will  prevent  the  washing  of  the  cement  from  the 
mixture. 

Forms  should  be  so  tight  as  to  prevent  the  entrance  of  sea  water 
after  depositing  the  concrete,  in  order  that  a  smooth  dense  surface 
may  be  obtained. 

The  combined  effect  of  freezing  and  of  sea  water  is  noted  on 
marine  structures  in  northern  latitudes  between  high  and  low  tide 
levels.  Under  these  conditions  the  disintegrating  effects  are  par- 
ticularly severe. 

Dense,  properly  hardened  concrete  is  not  affected  by  the  action 
of  sea  water.  Where  the  concrete  is  porous,  however,  it  is  likely 
to  be  damaged  by  frost  action,  especially  between  tides.  There  is  no 
evidence,  however,  that  porous  concrete  is  damaged  by  sea  water 
in  latitudes  where  there  is  no  frost. 

The  making  of  a  dense,  impermeable  concrete  by  the  use  of  a 
well-graded  aggregate,  rich  mixture,  proper  consistency,  and  good 
workmanship,  and  allowing  the  concrete  to  harden  under  favorable 
conditions  before  being  exposed  to  the  action  of  sea  water,  is  generally 


CONCRETE  IN  SEA  WATER  405 

conceded  to  be  an  efficient  means  of  satisfactorily  insuring  the  pres- 
ervation of  concrete  in  maritime  works. 

Concrete  Subjected  to  the  Action  of  Water  Containing  Alkalies. 
Investigations  concerning  the  effect  of  ground  waters  which  contain 
alkalies  on  concrete  have  disclosed  several  instances  of  apparent 
disintegration.  The  following  points  have  been  demonstrated  in 
regard  to  the  resistance  of  concrete  to  these  agencies : 

Concrete  in  which  poor  aggregates  and  lean  mixtures  have  been 
used  and  in  which  the  material  has  been  carelessly  placed,  when 
coming  in  contact  with  alkali  seepage  may  be  affected  thereby. 

The  aggregates  should  be  composed  of  materials  inert  to  alkalies 
present  in  the  water.  A  chemical  examination  of  the  sand  from  coun- 
try known  to  contain  alkaline  soils  is  recommended. 

Water  containing  substances  known  to  react  with  the  elements 
of  the  cement  should  be  kept  from  coming  in  contact  with  concrete 
until  the  latter  has  thoroughly  hardened. 

Care  should  be  taken  to  provide  a  smooth  surface  and  sufficient 
slope  to  the  extrados  of  the  arch  of  tunnel  linings  when  the  ground- 
water  level  lies  below  the  tunnel  grade  to  facilitate  the  flow  of  seep- 
age water  to  the  sides.  The  back  filling  over  the  arch  should  consist 
of  porous  material  such  as  coarse,  crushed  stone,  for  the  same  reason. 
Side-drains  should  be  used  where  necessary  and  connected  with  an 
underdrain,  which  should  be  provided  in  all  cases. 

The  measures  to  be  used  in  making  concrete  which  is  to  be  exposed 
to  the  action  of  these  deteriorating  agencies  in  order  to  prevent 
disintegration  are  the  same  as  recommended  for  sea  water  construc- 
tion. Impermeability  is  the  prime  requisite,  and  the  results  of  experi- 
ments and  practical  tests  indicate  that  concrete,  carefully  prepared, 
is  just  as  resistant,  if  not  more  so,  than  if  mixed  with  foreign  materials 
or  special  preparations. 

The  following  instructive  conclusions  on  the  effect  of  sea  water 
on  concrete  are  from  a  paper  by  Mr.  W.  Walters  Pagon,  read  before 
the  Engineers  Club  of  Baltimore.*  Though  somewhat  a  repetition 
of  the  previous  paper,  its  greater  detail  warrants  its  addition 
here. 

In  order  to  construct  concrete  that  will  have  the  greatest  resistive 
power  against  the  action  of  sea  water  (and  also  probably  of  alkali 
waters)  it  must  possess  the  following  characteristics: 

The  addition  of  puzzolan  in  some  form  is  widely  practiced  in 
Europe  and  appears  to  be  theoretically  correct.  It  has  not  been 
tried  in  America,  to  the  author's  knowledge,  but  is  worth  an  exhaus- 
*  "  Concrete,"  Vol.  9,  No.  4,  October,  1916. 


406  APPENDIX   II 

tive  test.  The  amount  should  not  be  over  one  part  nor  less  than 
one-half  part  for  each  part  of  cement. 

Waterproofing  with  substances  that  combine  chemically  with  the 
free  lime  ought  to  be  successful  and  is  worth  testing. 

Between  extreme  high  and  low  tides  the  concrete  surface  should 
be  faced  continuously,  without  joints,  with  about  3  inches  of  1  :  1J 
or  1  :  2  mortar  made  with  sand  as  specified  below,  well  cured  before 
coming  in  contact  with  the  sea  water.  Facing  must  be  placed  simul- 
taneously with  the  backing. 

The  cement  should  be  low  in  lime  and  alumina  and  contain  as 
little  gypsum  as  possible. 

Sand  must  be  silicious,  uniformly  graded  from  fine  to  coarse, 
with  not  less  than  50  per  cent  nor  more  than  70  per  cent  passing 
through  a  No.  20  sieve,  and  no  more  than  3  per  cent  passing  a  No. 
100  sieve  and  must  have  no  organic  matter  coating  the  grains.  It 
must  be  free  from  roots  and  easily  disintegrated  grains,  such  as 
feldspar,  shells,  limestone,  mica,  etc.  It  should  be  washed  free 
from  clay,  and  should  show  a  tensile  strength  for  1  :  3  specimens 
not  less  than  the  following  percentages  of  the  strength  of  standard 
Ottawa  sand  of  the  same  consistency,  using  the  brand  of  cement 
that  is  to  be  used  on  the  work: 

A  Percentage 

A«e-  Strength. 

1  day  85 

7  days  95 

28  days  100 

Where  concrete  must  be  exposed  to  sea  water  without  mortar 
facing,  gravel  should  not  be  used.  Broken  stone  should  be  hard, 
durable  trap,  granite  or  other  dense,  hard,  insoluble  stone.  It 
should  not  exceed  f  inch  in  size  and  should  be  free  from  crusher 
dust,  sand,  dirt,  organic  matter  or  other  foreign  substances.  The 
mixture  should  be  1  :  1J  :  3  or  1  :  2  :  4  or  should  be  proportioned 
for  maximum  density. 

Pure  fresh  water  should  be  used  in  sufficient  quantity  to  permit 
the  materials  to  be  well  puddled  and  spaded,  so  that  no  later  surface 
treatment  or  patching  will  be  require^,  but  not  sufficient  to  materially 
retard  the  setting  of  the  cement.  Care  must  be  exercised,  however, 
to  prevent  the  formation  of  laitance  or  pockets  of  neat  cement  or 
very  rich  mortar. 

Forms  should  be  tight  to  prevent  leakage  of  cement,  or,  where 
concrete  must  be  submerged  immediately,  to  prevent  contact  with 
the  sea  water. 


CONCRETE  IN  SEA  WATER  407 

Facing  should  be  reinforced  with  steel  well  covered  with  mortar 
and  securely  anchored  to  the  backing. 

No  surface  treatment  should  be  given. 

The  work  should  be  allowed  to  harden  for  two  weeks,  if  possible, 
before  coming  in  contact  with  sea  water.  Two  months  is  better. 

Sea  water  work  should  never  be  done  in  cold  weather,  with  tem- 
perature below  40  deg.  Fahr.  (4.4  deg.  Cent.). 

Where  possible,  pre-cast,  mortar-faced  blocks  cured  in  damp  sand 
for  at  least  one  month  should  be  used.  The  mortar  facing  should 
not  only  be  on  the  outside  of  the  block,  but  should  extend  on  the  faces 
which  form  the  bed  joints  and  vertical  joints.  In  this  way  the  facing 
will  be  continuous,  back  to  such  a  point,  that  no  water  can  get  into 
the  rear  of  the  block.  The  joints  between  the  blocks  should  be 
pointed  with  1  :  1  mortar  of  coarse  sand  to  eliminate  saturation. 

The  most  durable  surface  will  be  obtained  if  granite  or  other  dense 
stone  be  used  as  facing.  This  should  not  be  less  than  6  inches  thick, 
anchored  back  with  wrought-iron  clamps  and  pointed  with  1  :  1 
mortar  of  coarse  sand  and  cement  as  noted  above. 

On  mortar  or  concrete  surfaces  the  growth  of  barnacles,  moss, 
etc.,  will  frequently  afford  protection. 


APPENDIX  III 
REPORT  ON  WATERPROOFING  * 

THE  following  report  of  Committee  D-8  of  the  American  Society 
for  Testing  Materials  corroborates  the  author's  information  and 
experience  in  general  waterproofing  preceding  and  since  its  publica- 
tion. 

The  committee  reports  that  while  it  has  not  been  able  to  arrive 
at  sufficiently  definite  conclusions  to  enable  it  to  formulate  specifica- 
tions for  the  making  of  concrete  structures  waterproof  or  for  materials 
to  be  used  in  such  work,  it  has  reached  certain  general  conclusions 
which  may  be  of  assistance  to  the  constructor  in  securing  the  desired 
result  of  impermeable  concrete. 

Early  in  the  investigation,  the  work  was  found  to  sub-divide 
naturally  into  three  branches,  and  the  conclusions  reached  will  be 
grouped  in  order  under  these  sub-divisions,  which  are: 

1.  The  determination  of  causes  of  the  permeability  of  concrete  as 
usually  made  from  mixtures  of  Portland  cement,  sand  and  stone,  or 
other  coarse  aggregate,  in  proportions  of  from  1  cement,  2  sand  and 
4  stone,  to  1  cement,  3  sand  and  6  stone,  and  the  best  methods  of 
avoiding  these  causes. 

2.  The  rendering  of  concrete  more  waterproof  by  adding  to  ordi- 
nary mixtures  of  cement,  sand  and  stone,  other  substances,  which, 
either  by  their  void-filling  or  repellent  action,  would  tend  to  make 
the  concrete  less  permeable. 

3.  The  treatment  of  exposed  surfaces  after  the  concrete  or  mortar 
has  be3n  put  in  place  and  hardened  more  or  less,  either  by  penetra- 
tive, void-filling  or  repellent  liquids,  making  the  concrete  itself  less 
permeable  or  by  extraneous  protective  coatings,  preventing  water 
having  access  to  the  concrete. 

Considering  these  several  sub-divisions  separately  and  in  the  order 
named,  the  committee  finds : 

1.  Causes  of  Permeability  of  Concrete.  In  the  laboratory  and 
under  test  conditions  using  properly  graded  and  sized  coarse  and  fine 
aggregates,  in  mixtures  ranging  from  1  cement,  2  sand  and  4  stone, 
to  1  cement,  3  sand  and  6  stone,  impermeable  concrete  can  invariably 

*  Proceedings,  American  Society  for  Testing  Materials,  Vol.  13,  1913,  p.  459. 

408 


REPORT  ON  WATERPROOFING  409 

be  produced.  That  even  with  sand  of  poor  granulometric  composi- 
tion, with  mixtures  as  rich  as  1  cement,  2  sand  and  4  stone,  per- 
meable concrete  is  seldom,  if  ever,  found  and  is  a  rare  occurrence  with 
mixtures  of  1  cement,  3  sand  and  6  stone.  But  the  fact  remains, 
nevertheless,  that  the  reverse  obtains  in  actual  construction,  per- 
meable concretes  being  encountered  even  with  1  cement,  2  sand  and 
4  stone  mixtures  and  are  of  frequent  occurrence  where  the  quantity 
of  the  aggregate  is  increased.  This  we  attribute  to: 

(a)  Defective  workmanship,  resulting  from  improper  propor- 
tioning, lack  of  thorough  mixing,  separation  of  the  coarse  aggregate 
from  the  fine  aggregate  and  cement  in  transporting  and  placing  the 
mixed  concrete,  lack  of  density  through  insufficient  tamping  or 
spading,  and  improper  bonding  of  work  joints,  etc. 

(6)  The  use  of  imperfectly  sized  and  graded  aggregates: 

(c)  The  use  of  excessive  water,  causing  shrinkage  cracks  and  for- 
mation of  laitance  seams. 

(d)  The  lack  of  proper  provision  to  take  care  of  expansion  and 
contraction,  causing  subsequent  cracking. 

Theoretically,  none  of  these  conditions  should  prevail  on  properly 
designed  and  supervised  work,  and  are  avoided  in  the  laboratory 
and  in  the  field,  under -test  conditions,  where  speed  of  construction 
and  cost  are  negligible  items,  instead  of  being  governing  features 
as  they  must  be  in  actual  construction.  Properly  graded  sands  and 
coarse  aggregares  are  rarely,  if  ever,  found  in  nature  in  sufficient 
quantities  to  be  available  for  large  construction,  and  the  effect  of 
poorly  graded  aggregates  in  producing  permeable  concrete  is  aggre- 
vated  by  poor  and  inefficient  field  work.  Even  if  we  could  afford 
the  added  expense  of  screening  and  remixing  the  aggregates  so  as  to 
secure  proper  granulometric  composition  to  give  the  density  required 
and  to  make  untreated  concretes  impermeable,  it  is  seemingly  a 
commercial  impossibility  on  large  construction  to  obtain  workman- 
ship even  approximating  that  found  in  laboratory  work.  It  there- 
fore seems  that  we  can  secure  impermeable  concrete  most  economic- 
ally by  adopting  some  special  waterproofing  treatment. 

2.  Addition  of  Foreign  Substances  to  Cement  or  During  Mixture. 
The  committee  finds  that  in  consequence  of  the  conditions  outlined 
above,  the  use  of  substances  calculated  to  make  the  concrete  more 
impermeable,  either  incorporated  in  the  cement  or  added  to  the  con- 
crete during  mixing,  has  become  general.  This  has  resulted  in  the 
development  and  placing  on  the  market  of  numerous  patented  or 
proprietary  waterproofing  compounds,  the  composition  of  which  is 
more  or  less  of  a  trade  secret. 


410  APPENDIX  III 

While  it  has  been  impossible  for  the  committee  to  test  all  of  the 
special  waterproofing  compounds  being  placed  on  the  market,  it  has 
investigated  a  sufficient  number  of  these,  as  well  as  the  use  of  certain 
very  finely  divided,  naturally  occurring  or  readily  obtainable  com- 
mercial mineral  products,  such  as  finely  ground  sand,  colloidal  clays, 
hydrated  lime,  etc.,  to  form  a  general  idea  of  the  value  of  the  different 
types.  The  committee  finds: 

(a)  That  the  majority  of  patented  and  proprietary  integral  com- 
pounds tested  have  little  or  no  permanent  effect  on  the  permeability 
of  concrete  and  that  some  of  these  even  have  an  injurious  effect  on 
the  strength  of  mortar  and  concrete  in  which  they  are  incorporated ; 

(6)  That  the  permanent  effect  of  such  integral  waterproofing 
additions,  if  dependent  on  the  action  of  organic  compounds,  is  very 
doubtful; 

(c)  That  in  view  of  their  possible  effect,  not  only  upon  the  early 
strength,  but  also  upon  the  durability  of  concrete  after  considerable 
periods,  no  integral  waterproofing  material  should  be  used  unless 
it  has  been  subjected  to  long-time  practical  tests  under  proper  observa- 
tion to  demonstrate  its  value,  and  unless  its  ingredients  and  the  pro- 
portion in  which  they  are  present  are  known; 

(d)  That  in  general,  more  desirable  results  are  obtainable  from 
inert  compounds  acting  mechanically  than  from  active   chemical 
compounds  whose  efficiency  depends  on  change  of  form  through 
chemical  action  .after  addition  to  the  concrete; 

(e)  That  void-filling  substances  are  more  to  be  relied  upon  than 
those  whose  value  depends  on  repellent  action; 

(/)  That,  assuming  average  quality  in  sizing  of  the  aggregates 
and  reasonably  good  workmanship  in  the  mixing  and  placing  of  the 
concretes,  the  addition  of  from  10  to  20  per  cent  of  very  finely  divided 
void-filling  mineral  substances  may  be  expected  to  result  in  the  pro- 
duction of  concrete  which  under  ordinary  conditions  of  exposure 
will  be  found  impermeable,  provided  the  work  joints  are  properly 
bonded,  and  cracks  do  not  develop  on  drying  or  through  change  in 
volume  due  to  atmospheric  changes,  or  by  settlement. 

3.  External  Treatments.  While  external  treatment  of  concrete 
would  not  be  necessary  if  the  concrete  itself,  either  naturally  or  by 
the  addition  of  waterproofing  material,  was  impermeable  to  water, 
it  has  been  found  in  practice  that  in  large  construction,  no  matter 
how  carefully  the  concrete  itself  has  been  made,  cracks  are  apt  to 
develop,  due  to  shrinkage  in  drying  out,  expansion  and  contraction 
under  change  of  temperature,  moisture  content  and  through  settle- 
ment. 


REPORT  ON  WATERPROOFING  411 

It  is,  therefore,  often  advisable  on  important  construction  to 
anticipate  and  provide  for  the  possible  occurrence  of  such  cracks  by 
external  treatment  with  protective  coatings.  Such  coating  must  be 
sufficiently  elastic  and  cohesive  to  prevent  the  cracks  extending 
through  the  coating  itself.  The  application  of  merely  penetrative 
void-filling  liquid  washes  will  not  prevent  the  passage  of  water  due 
to  cracking  of  the  concrete.  The  committee  has,  therefore,  divided 
surface  treatments  into  two  heads: 

(a)  Penetrative  void-filling  liquid  washes. 

(6)  Protective  coatings,  including  all  surface  applications  intended 
to  prevent  water  coming  in  contact  with  the  concrete. 

While  many  penetrative  washes  are  efficient  in  rendering  concrete 
waterproof  for  limited  periods,  their  efficiency  is  apt  to  decrease  with 
time  and  it  may  be  necessary  to  repeat  such  treatment.  Some  of 
these  washes  may  be  objectionable,  due  to  discoloring  the  surface  to 
which  they  are  applied.  The  committee,  therefore,  believes  that  the 
first  effort  should  be  made  to  secure  a  concrete  that  is  impermeable 
in  itself  and  that  penetrative  void-filling  washes  should  only  be  re- 
sorted to  as  a  corrective  measure. 

While  protective  extraneous  bituminous  or  asphalt  coatings  are 
unnecessary,  so  far  as  the  major  portion  of  the  concrete  surface  is 
concerned,  provided  the  concrete — either  in  itself  or  through  the  addi- 
tion of  internal  compounds — is  made  impermeable,  they  are  valuable 
as  a  protection  where  cracks  develop  in  a  structure.  It  is  therefore 
recommended  that  combination  of  the  two  methods — integral  and 
extraneous  waterproofing — be  adopted  in  especially  difficult  or  im- 
portant work. 

Considering  the  use  of  bituminous  or  asphaltic  coatings,  the  com- 
mittee finds: 

(a)  That  such  protective  coatings  are  often  subject  to  more  or 
less  deterioration  with  time,  and  may  be  attacked  by  injurious  vapors 
or  deleterious  substances  in  solution  in  the  water  coming  in  contact 
with  them. 

(6)  That  the  most  effective  method  for  applying  such  protec- 
tion is  either  the  setting  of  a  course  of  impervious  brick,  dipped  in 
bituminous  material,  into  a  solid  bed  of  bituminous  material,  or  the 
application  of  a  sufficient  number  of  layers  of  satisfactory  membra- 
nous material  cemented  together  with  hot  bitumen. 

(c)  That  their  durability  and  efficiency  are  very  largely  dependent 
on  the  care  with  which  they  are  applied. 

Such  care  refers  particularly  to  proper  cleaning  and  preparation 
of  the  concrete  to  insure  as  dry  a  surface  as  possible  before  applica- 


412  APPENDIX  III 

tion  of  the  protective  covering,  the  lapping  of  all  joints  of  the  mem- 
branous layers,  and  their  thorough  coating  with  the  protective  mate- 
rial. The  use  of  this  method  of  protection  is  further  desirable  because 
proper  bituminous  coverings  offer  resistance  to  stray  electrical  cur- 
rents. 

So  far,  the  committee  has  considered  only  concretes  of  the  usual 
proportions,  namely,  those  ranging  from  1  cement,  2  sand  and  4  stone, 
to  1  cement,  3  sand,  and  6  stone.  It  has  been  suggested  that  im- 
permeable concretes  could  be  assured  by  using  mixtures  considerably 
richer  in  cement.  While  such  practice  would  probably  result  in  an 
immediate  impermeable  concrete,  it  is  believed  by  many  that  the 
advantage  is  only  temporary,  as  richer  concretes  are  more  subject 
to  check  cracking  and  are  less  constant  in  volume  under  changes  of 
conditions  of  temperature,  moisture,  etc.  Therefore,  the  use  of  more 
cement  in  mass  concrete  would  cause  increased  cracking,  unless 
some  means  of  controlling  the  expansion  and  contraction  be  dis- 
covered. With  reinforced  concrete  the  objection  is  not  so  great,  as 
the  tendency  to  cracking  is  more  or  less  counteracted  by  the  re- 
inforcement. 

It  has  also  been  suggested  that  the  presence  in  the  cement  of  a 
larger  percentage  of  very  fine  flour  might  result  in  the  production  of 
a  denser  and  more  impermeable  concrete,  through  the  formation  of  a 
larger  amount  of  colloidal  gels. 

Neither  of  these  suggestions  have  been  especially  investigated 
by  the  committee.  Both  appeal  to  the  committee,  however,  for  the 
reason  that  they  substitute  active  cementitipus  substances  for  the 
largely  inactive  void-filling  materials  previously  recommended,  thus 
increasing  the  strength  of  the  concrete. 

In  conclusion,  thp  committee  would  point  out  that  no  addition 
of  waterproofing  compounds  or  substances  can  be  relied  upon  to 
completely  counteract  the  effect  of  bad  workmanship,  and  that  the 
production  of  impermeable  concrete  can  only  be  hoped  for  where 
there  is  determined  insistance  on  good  workmanship. 


APPENDIX    IV 
GLOSSARY  OF  TERMS  USED  IN  THE  WATERPROOFING  INDUSTRY 

Acid  Sludge.  A  waste  mixture  of  sulphonated  hydrocarbons  resulting  from 
the  treatment  of  bitumens  with  sulphuric  acid. 

Aggregate.  The  inert  material,  such  as  sand,  gravel,  shell,  slag  or  broken 
stone,  or  combinations  thereof,  with  which  the  cementing  material  is  mixed  to 
form  a  mortar  or  concrete. 

Albertite.  A  soft  jet  black  mineral  (asphaltic  hydrocarbon)  derived  from 
petroleum  by  natural  oxidation,  obtained  in  Canada. 

Alum.  A  white  crystalline  substance  consisting  of  a  hydrated  double  sul- 
phate of  aluminum  and  potassium.  See  Chapter  V. 

Anthracene.     A  waxy  crystalline  hydrocarbon  found  principally  in  coal  tars. 

Artificial  Bitumens.  Hydrocarbon  residues  produced  by  the  partial  or  frac- 
tional distillation  of  bitumen. 

Artificial  Gilsonite.  A  product  obtained  from  the  distillation  of  a  mixture  of 
fish  remains  and  wood  and  redistillation  of  the  resulting  oil. 

Asbestine.  A  trade  name  for  a  certain  grade  of  powdered  asbestos  used  in 
paints  as  a  filler. 

Asbestos.  A  mineral  of  fibrous  crystalline  structure  composed,  chemically, 
of  silicates  of  lime  and  magnesia,  and  alumina.  See  Chapter  V. 

Asbestos  Felt.     Sheets  made  of  asbestos  shreds.     See  Chapter  V. 

Ash  Water  Glass.     Same  as  water  glass. 

Asphalt.  Solid  or  semi-solid  native  bitumens,  solid  or  semi-solid  bitumens 
obtained  by  refining  petroleums,  or  solid  or  semi  solid  bitumens  which  are  combi- 
nations of  the  bitumens  mentioned  with  petroleums  or  derivatives  thereof,  which 
melt  on  the  application  of  heat,  and  which  consist  of  a  mixture  of  hydrocarbons 
and  their  derivatives  of  complex  structure,  largely  cyclic  and  bridge  compounds. 

Asphalt  Cement.  A  fluxed  or  unfluxed  asphaltic  material,  especially  prepared 
as  to  quality  and  consistency. 

Asphalt  Mastic.  A  term  frequently  applied  to  refined  asphalt,  particularly 
to  that  obtained  from  bituminous  rocks.  A  mixture  of  fine  mineral  matter  and 
asphalt. 

Asphalt  Pavement.  A  pavement  composed  of  a  mixture  of  asphalt  and  sand 
or  powdered  mineral  dust  or  both. 

Asphalt  Putty.  A  mixture  of  a  liquid  and  a  -solid  asphalt  (and  fine  mineral 
matter,  usually)  or  asphalt  and  coal-tar  pitch,  having  a  particular  consistency. 

Asphaltenes.*  The  components  of  the  bitumen  in  petroleum,  petroleum 
products,  malthas,  asphalt  cements,  and  solid  native  bitumens,  which  are  soluble 
in  carbon  disulphide,  but  insoluble  in  paraffin  naphthas. 

Asphaltic.     Similar  to,  or  essentially  composed  of,  asphalt. 

*  Adopted  by  the  American  Reporters  on  Communication  No.  10  at  the  third  International 
Road  Congress. 


414  APPENDIX  IV 

Asphaltic  Coal.  Solid  forms  of  asphalt  (originally  derived  from  petroleum) 
which,  through  loss  of  their  oil  content,  by  oxidation,  resemble  glance  coal. 

Asphaltic  Concrete.     Broken  stone  bound  together  with  asphaltic  cement. 

Asphaltic  Limestone.  Limestone  or  limestone  sands  naturally  impregnated 
with  asphalt  or  maltha,  and  known  as  "  asphalt  "  in  Europe. 

Asphaltic  Oils.     Asphaltic  petroleums. 

Asphaltic  Petroleums.     Petroleums  containing  an  asphaltic  base. 

Asphaltic  Sandstone.  Sandstone  naturally  impregnated  with  asphalt  or 
maltha  and  known  as  "  asphalt  "  in  Europe. 

Asphaltite.     Same  as  asphaltic  coal. 

Asphaltum.     The  Latin  form  of  the  English  word  asphalt. 

Bakelite.  A  hard  amber-like  substance  manufactured  from  the  coal-tar 
derivatives  phenol  and  formaldehyde.  See  Chapter  V. 

Bank-run  Gravel.     The  normal  product  of  a  gravel  bank. 

Barret  Specification  Felt.  Trade  name  for  a  proprietary  tar-treated  roofing 
felt. 

Baume  Gravity.  An  arbitrary  scale  of  specific  gravity  or  density  of  liquids, 
usually  expressed  as  deg.  Baume,  or  °  B.  on  a  hydrometer.  See  Chapter  XII. 

Benzene.     Benzol  (C6H6).     See  Chapter  V. 

Benzine.     A  light  and  volatile  fraction  of  petroleum.     See  Chapter  V. 

Benzol.  A  light,  volatile,  colorless  coal-tar  distillate  of  the  formula  CfiHR. 
See  Chapter  V. 

Bermudez  Asphalt.     A  very  pure  semi-solid  native  asphalt  from  Bermudez. 

Binder.  The  bituminous  cementing  material  employed  in  the  membrane 
system  of  waterproofing. 

Bitumen.  A  natural  hydrocarbon  mixture  of  mineral  occurrence,  widely 
diffused  in  various  forms  which  grade  by  imperceptible  degrees  from  a  light  gas  to 
a  solid;  commercially  the  term  includes  only  the  heavy  liquid  and  solid  asphalts. 
Frequently  coal-tar  pitch  is  so  referred  to. 

Bituminous.     A  term  applied  to  materials  containing  bitumen. 

Bituminous  Cement.  A  bituminous  material  suitable  for  use  as  a  binder 
having  cementing  qualities  which  are  dependent  mainly  on  its  bituminous  char- 
acter. 

Bituminous  Emulsion.  A  mixture  of  a  bituminous  oil  and  water  made 
miscible  through  the  action  of  a  saponifying  agent  or  alkaline  soap. 

Bituminous  Paints.  Mixtures  of  liquid  paraffin  and  asphalt  or  coal-tar; 
mixtures  of  bitumen  with  some  drying  oil.  See  Chapter  V. 

Bituminous  Putty.  A  mixture  of  bituminous  materials  and  whiting  or  other 
mineral,  of  a  putty-like  consistency. 

Bituminous  Rock.     Same  as  rock  asphalt. 

Blown  Asphalt.  Asphalt  through  which  air  has  been  blown  during  the 
process  of  refining. 

Blown  Oils.     Blown  petroleum. 

Blown  Petroleum.*  Semi-solid  or  solid  products  produced  primarily  by  the 
action  of  air  upon  originally  fluid  native  bitumens  which  are  heated  during  the 
blowing  process. 

Building  Paper.  A  paper,  usually  a  heavy  grade  and  strong,  sized  with  rosin 
to  make  it  water  resisting  and  used  to  sheath  buildings  to  exclude  drafts. 

*Adopted  by  the  American  Reporters  on  Communication  No.  10  at  the  third  International 
Road  Congress. 


GLOSSARY  OF  TERMS   USED   IN  WATERPROOFING        415 

Built-up  Roofs.  Roofing  consisting  of  several  plies  of  treated  felt  cemented 
with  asphalt  or  coal-tar  pitch.  See  Chapter  III. 

Burlap.     A  woven  fabric  made  of  jute.     See  Chapter  V. 

Byerlite.  Common  and  trade-name  of  a  blown  asphaltic  petroleum  dis- 
tinguished from  ordinary  blown  petroleums  principally  by  the  use  of  oxygen  in- 
stead of  air  in  the  blowing  process. 

Caffall  Process.  A  proprietary  process  for  applying  paraffin  to  exterior 
masonry  surfaces. 

Calcium  Compounds.     Salts  of  metal  calcium  or  lime.     See  Chapter  V. 

Caoutchouc.  A  hydrocarbon  with  the  approximate  formula  of  CioHi6  and 
possessing  properties  similar  to  India  rubber. 

Carbenes.*  The  components  of  the  bitumen  in  petroleums,  petroleum 
products,  malthas,  asphalt  cements,  and  solid  native  bitumens,  which  are  soluble 
in  carbon  disulphide,  but  insoluble  in  carbon  tetrachloride. 

Carbon  Bisulphide.  The  volatile  and  extremely  inflammable  compound  of 
carbon  and  sulphur  (CS2) . 

Carbon  Disulphide.     Same  as  carbon  bisulphide. 

Carbon  Tetrachloride.  A  volatile  noninflammable  compound  of  carbon  and 
chlorine  (C-Clt). 

Carborundum.  An  artificial  abrasive  material  resulting  from  the  burning, 
in  an  electric  furnace,  of  a  mixture  of  sand,  coke,  sawdust  and  salt. 

Casein.     An  albumin  found  in  milk.     See  Chapter  V. 

Cement.  An  adhesive  substance  used  for  uniting  particles  of  materials  to 
each  other.  Ordinarily  applied,  only  to  calcined  "  cement  rock,"  or  to  arti- 
ficially prepared,  calcined,  and  ground  mixtures  of  limestone  and  silicious  mate- 
rials. Sometimes  used  to  designate  bituminous  binder  used  in  waterproofing. 

Cement  Floor.  A  name  commonly  applied  to  concrete  floors  with  or  without 
a  mortar  top. 

Cerasin.     Ozocerite. 

Cerite.     Ozocerite. 

China  Clay.     Kaolin. 

Chinawood  Oil.  Oil  pressed  from  the  seeds  of  the  wood-oil  tree  of  China 
and  Japan.  See  Chapter  V. 

Choctaw.  Name  of  mining  locality  (in  Oklahoma)  of  grahamite;  some- 
times, but  incorrectly  used  for  grahamite. 

Clay.  Finely  divided  earth,  generally  silicious  and  aluminous,  which  will 
pass  a  200-mesh  sieve. 

Coal  Tar.  The  mixture  of  hydrocarbon  distillates,  mostly  unsaturated  ring 
compounds,  produced  in  the  destructive  distillation  of  coal.  See  Chapter  V. 

Coal-tar  Pitch.  The  residue  (of  a  viscous  consistency)  resulting  from  the 
distillation  of  coal-tar.  See  Chapter  V. 

Coat.  (1)  The  total  result  of  one  or  more  surface  applications.  (2)  To 
apply  a  coat. 

Coke-oven  Tar.  Coal  tar  produced  in  by-product  coke  ovens  in  the  manu- 
facture of  coke  from  bituminous  coal.  See  Chapter  V. 

Colloidal  Material.  A  gelatinous  substance,  resembling  glue  or  jelly,  and 
consisting  of  microscopically  fine  particles  of  matter. 

Colophony.     Rosin. 

*  Adopted  by  the  American  Reporters  on  Communication  No.  10  at  the  third  International 
Road  Congress. 


416  APPENDIX  IV 

Compressed  Asphalt.  A  European  (particularly  French)  term  for  rock  asphalt 
pavement. 

Concrete  Floor  Hardener.  A  powdered  metal  or  mineral  usually  troweled  on, 
or  a  liquid  chemical  reagent  usually  brushed  on,  the  surface  of  a  concrete  floor 
to  harden  same. 

Concrete  Primer.  A  thin  liquid  compound  applied  as  a  first  coat  to  a  con- 
crete surface  preparatory  to  being  coated  with  a  more  viscous  compound. 

Consistency.*     The  degree  of  solidity  or  fluidity  of  bituminous  materials. 

Corundum.  A  crystalline  mineral  abrasive  mined  in  the  United  States  and 
ground  for  use. 

Cotton  Drill.     A  woven  cotton  fabric.     See  Chapter  V. 

Cracked  Oil.  Petroleum  residuum  which  have  been  overheated  in  the  proc- 
ess of  manufacture. 

Cracking.  The  process  of  breaking  down  hydrocarbon  molecules  by  the 
application  of  heat. 

Crude  Asphalt.     Unrefined  asphalt. 

Crude  Oil.     Unrefined  oil. 

Crude  Tar.     Unrefined  coal  tar. 

Cut-back  Products.  Petroleum,  or  tar-residuums,  which  have  been  fluxed 
each  with  its  own  or  similar  distillate,  to  a  desired  consistency. 

Dampproofing.  The  process  of  treating  masonry  internally  or  externally, 
to  prevent  dampness  or  moisture  from  penetrating  the  masonry. 

Dead  Oils.     Heavy  oils  with  a  density  greater  than  water  distilled  from  tars. 

Dehydrated  Tars.     Crude  tar  from  which  all  water  has  been  removed. 

Destructive  Distillation.  The  distillation  of  organic  compounds  at  suf- 
ficiently high  temperatures  so  that  their  identity  is  destroyed. 

Dipping  Compound.  Bituminous  compound  used  for  coating  pipes  and  iron 
tunnel  segments  to  preserve  them  against  rust. 

Drainage.     Provision  for  the  disposition  of  water  in  or  about  a  structure. 

Dust.  Earth  or  other  matter  in  fine,  dry  particles,  so  attenuated  that  they 
can  be  raised  and  carried  by  air  currents.  The  product  of  the  crusher  passing 
through  a  fine  sieve. 

Eastern  Petroleum.  Petroleum  found  in  the  eastern  part  of  the  United  States, 
principally  Pennsylvania. 

Elaterite.  A  soft  elastic  variety  of  asphalt,  resembling  rubber,  Also  an 
appropriated  name  of  a  proprietary  waterproofing  compound.  See  Chapter  V. 

Emulsion.  A  combination  of  water  and  oily  material  made  miscible  through 
the  action  of  a  saponying  agent. 

Expansion  Joint.  A  separation  of  the  mass  of  a  structure,  usually  in  the 
form  of  a  joint  filled  with  elastic  material,  which  provides  the  means  for  slight 
movement  in  the  structure. 

Fabric.     A  cotton  cloth  or  burlap  treated  with  asphalt  or  coal-tar  pitch. 

Felt.  A  soft  form  of  paper  sheet  composed  chiefly  of  pulp  and  rags  and 
saturated  with  coal-tar  pitch  or  asphalt.  See  Chapter  V. 

Filler.  (1)  Relatively  fine  material  used  to  fill  the  voids  in  concrete  aggre 
gate.  (2)  Material  used  to  fill  the  voids  in  expansion  joints. 

Fixed  Carbon.*  The  organic  matter  of  the  residual  coke  obtained  upon 
burning  hydrocarbon  products  in  a  covered  vessel  in  the  absence  of  free  oxygen. 

Flashing.     A  piece  of  metal  or  other  waterproof  material  used  to  keep  water 

*  Adopted  by  the  Am,  Soc.  for  Testing  Materials. 


GLOSSARY  OF  TERMS  USED  IN  WATERPROOFING        417 

from  penetrating  the  joints  between  a  wall  or  projection,  and  the  roof  or  other 
flat  part  of  the  structure.     See  Chapter  III. 

'Floating.     Smoothing,  with  a  trowel,  the  surface  of  mortar  or  concrete. 

Flux.*  Bitumens,  generally  liquid,  used  in  combination  with  harder  bitu- 
mens for  the  purpose  of  softening  the  latter. 

Free  Carbon.  In  tars,  organic  matter  which  is  insoluble  in  carbon  bisul- 
phide. See  Chapter  VII. 

Fuller's  Earth.  A  fine-grained  earthy  material  of  cretaceous  formation  and 
resembling  clay  in  appearance. 

Furring  Compound.     A  compound  used  to  bond  plaster  to  masonry. 

Gaging  Water.  Water  (in  measured  quantities)  used  in  mixing  mortar  or 
concrete  to  a  required  consistency. 

Gas  Black.     Soot  from  natural  gas. 

Gas-drip.  A  condensate  from  illuminating  gas,  present  to  a  greater  or  less 
degree  in  all  gas  mains  and  tanks  and  an  effective  solvent  of  most  bituminous 
materials. 

Gas-house  Coal  Tar.  Coal-tar  produced  in  gas-house  retorts  in  the  manu- 
facture of  illuminating  gas  from  bituminous  coal. 

Gasoline.     A  very  volatile  distillate  of  petroleum.     See  Chapter  V. 

German  Wax.     A  manufactured  wax  or  blend  of  beeswax  and  other  waxes. 

Gilsonite.  Glance  pitch;  a  pure  hard  lustrous  asphalt  found  principally  in 
Utah,  U.  S.  A.  See  Chapter  V. 

Glance  Pitch.     A  very  pure  solid  asphalt  or  gum  asphalt. 

Grahamite.     A  pure,  solid  lusterless  asphalt.     See  Chapter  V. 

Graphite.  A  soft  dark-colored  form  of  carbon  with  considerable  luster.  See 
Chapter  V. 

Gravel.  Small  stones  or  pebbles,  usually  found  in  natural  deposits  more  or 
less  intermixed  with  sand,  clay,  etc.,  but  in  which  mixture  the  particles  which 
will  not  pass  a  10-mesh  sieve  predominate. 

Grit.  Stone  chips,  slag  chips,  small  pebbles  or  rounded  rock  particles  graded 
or  ranging  in  size  between  |  and  f  inch. 

Ground  Water.  That  part  of  rain,  hail,  or  snow,  that  has  percolated  through 
and  accumulated  in  the  ground  as  water  chiefly  in  consequence  of  an  underlying 
impervious  strata. 

Ground- water  Level.     The  upper  surface  of  ground  water.     See  Chapter  I. 

Grout.  A  mixture  of  cement  and  water  or  cement  sand  and  water  of  thinner 
consistency  than  mortar.  See  Chapter  V. 

Grouting.  The  process  of  injecting  grout  or  mortar  to  fill  small  holes  and 
seams  in  and  around  subsurface  structures.  See  Chapter  II. 

Gum.     Varnish  gum;  loosely  applied  to  asphalt. 

Gum  Resins.     Resins  exuding  from  cuts  in  pines. 

Gumlac.     Shellac. 

Gunite.  Trade  name  for  the  mortar  made  and  "shot"  from  the  cement 
gun.  See  Chapter  II. 

Gutta-percha.  A  substance  consisting  of  a  dried  milky  juice  in  many  respects 
similar  to  caoutchouc,  but  not  elastic;  extracted  from  certain  trees  in  the  iropics. 

Gypsum.  Erroneously  referred  to  as  plaster  of  Paris  but  actually  a  hydrated 
calcium  sulphate  (CaSO4,  2H20). 

*  Adopted  by  the  American  Reporters  on  Communication  No.  10  at  the  third  International 
Hoad  Congress. 


418  APPENDIX  IV 

High  Carbon  Tars.  Tars  containing  a  high  percentage  of  free  carbon  (between 
15  and  25  per  cent). 

Hot  Stuff.  Washing  soda  (carbonate  of  lime)  when  used  to  quicken  the  set- 
ting time  of  mortar.  Colloquially,  also  hot  molten  asphalt,  or  coal-tar  pitch,  or 
mastic  made  from  these. 

Hydrated  Lime.  A  finely  divided  white  powder,  made  of  ordinary  lime  to 
which  has  been  added  just  sufficient  water  to  insure  complete  slaking,  and 
leaving  the  product  dry.  See  Chapter  V. 

Hydrocarbons.  Chemical  compounds  composed  of  the  elements  hydrogen 
and  carbon. 

Hydrolithic.  Proprietary  trade  name  applied  to  the  integral  system  of 
waterproofing. 

Hydrolytic.  Name  commonly  applied  to  materials  used  in  integral  water- 
proofing which  tend  to  prevent  the  percolation  of  water  through  the  treated 
masonry. 

Hydrex  Compound.     Trade  name  for  a  proprietary  asphalt. 

Imitatite,     A  black,  hard  variety  of  bitumen. 

Impsomite.     A  solid  bitumen  resembling  gilsonite,  found  in  Oklahoma,  U.S.A. 

Integral  Compound.  A  material  incorporated  in  mortar  or  concrete,  previous 
to  or  during  mixing,  to  waterproof  same.  See  Chapter  II. 

Integral  System.  The  process  .of  incorporating  waterproofing  materials  in 
mass  mortar  or  concrete.  See  Chapter  II. 

Iron  (Powdered).     Cast  iron  or  pig  iron  in  powder  form. 

Isinglass.  The  dried  swimming  bladders  of  several  varieties  of  fish  from 
which  gelatine  is  extracted. 

Joint  Filler.  Any  compound  used  for  filling  joints  between  moving  parts 
of  steel  or  masonry  (structures)  subject  to  expansion,  contraction  and  vibration. 
See  Chapter  IV. 

Kaolin.     A  fine  clay  the  purity  of  which  gives  it  a  white  color. 

Lake  Pitch.  A  plastic  porous,  and  about  50  per  cent  impure  asphalt  from 
the  asphalt  "  lake  "  in  the  island  of  Trinidad. 

Land  Pitch.  A  surface  deposit  of  solid  Trinidad  Lake  asphalt  which  is 
tougher  and  more  tenacious  than  the  "  lake  "  asphalt. 

Land  Plaster.  Powdered  gypsum;  also,  but  incorrectly,  used  to  designate 
plaster  of  Paris. 

Lap  Cement.  A  liquid  bituminous  compound  used  for  cementing  the  laps 
of  ready  roofing. 

Larutan  Compound.     Trade  name  of  a  proprietary  asphalt. 

Larutan  System.  Application  of  a  waterproofing  membrane  in  the  form  of 
small  squares  of  asphalt-treated  cotton  fabric.  See  Chapter  II. 

Layer.     A  course  or  coat  made  in  one  application. 

Lime.  A  white  substance  resulting  from  the  burning  of  limestone.  See 
Chapter  V. 

Linseed  Oil.     Oil  obtained  from  the  seed  of  flax  by  pressing.     See  Chapter  V. 

Lithocarbon.  A  commercial  name  for  an  asphaltic  limestone  found  in 
Uvalde,  Texas,  U.  S.  A. 

Low  Carbon  Tars.  Tars  containing  a  low  percentage  of  free  carbon  (between 
5  and  15  per  cent). 

Maltha.  A  natural  or  artificial  asphalt  containing  sufficient  lighter  compounds 
to  be  liquid. 


GLOSSARY  OF  TERMS  USED   IN   WATERPROOFING        419 

Malthene.  Those  portions  of  asphalt  and  similar  materials  soluble  in  both 
carbon  bisulphide  and  petrolic  ether  and  not  readily  volatile  at  a  temperature  of 
163  deg.  Cent. 

Manjak.  A  pure,  black,  lustrous  bitumen  from  Barbadoes,  probably  related 
to  grahamite. 

Mastic.  A  mixture  of  fine  mineral  matter  and  asphalt  or  coal-tar  pitch, 
applicable  in  a  heated  condition.  See  Chapter  V. 

Mastic  Rock.     Rock  asphalt. 

Membrane.  In  waterproofing,  a  thin  layer  or  layers  of  bituminous  material 
with  or  without  fabric  reinforcement,  placed  on  or  about  a  structure. 

Membrane  System.  The  system  of  applying  an  elastic,  membranous  water- 
proofing material.  See  Chapter  II. 

Metal  Primer.  A  first  coat  of  paint  or  preserving  compound  applied  to  iron 
or  steel. 

Mineral  Naphtha.     A  volatile  petroleum  distillate  heavier  than  gasoline. 

Mineral  Oil.     Petroleum. 

Mineral  Pitch.     A  popular  name  for  asphalt. 

Mineral  Rubber.     A  bitumen  of  rubbery  consistency. 

Mineral  Tar.     A  liquid  bitumen,  of  a  viscid,  tarry  nature. 

Mineral  Wax.     A  common  term  for  ozocerite. 

Minwax.     A  proprietary  asphalt. 

Mortar.  A  mixture  of  sand,  cement,  or  lime  (or  both)  and  water  mixed  to 
a  paste  consistency. 

Naphtha.  A  volatile  petroleum  hydrocarbon  distillate  heavier  than 
gasoline. 

Naphthalene.  A  white  solid  crystalline  hydrocarbon,  occurring  principally 
in  coal  tar,  of  the  chemical  formula  Ci0H8. 

Native  Bitumens.  Bitumens  occurring  in  nature,  and  for  waterproofing 
purposes,  generally  as  liquids,  viscous  liquids  or  solids. 

Native  Paraffin.     Ozocerite. 

Natural  Cement.  A  fine  cementing  powder  made  by  burning  and  grinding  a 
cement  rock  at  a  somewhat  lower  heat  than  Portland  cement.  See  Chapter  V. 

Neponsit  Felt.     Trade  name  for  a  proprietary  roofing  felt. 

Neutral  Oil.     Neutral  mineral  oil. 

Oil  Asphalts.  Artificial  oil  pitches  or  asphaltic  cements  produced  as  a  resid- 
uum from  asphaltic  petroleum. 

Oil  Pitches.     More  or  less  hard  oil  asphalts. 

Oil-gas  Tars.  Complex  hydrocarbon  liquids  produced  by  cracking  oil  vapors 
at  high  temperatures  in  the  manufacture  of  oil  gas  or  carburetted  water  gas. 

Oil-tar  Pitch.  A  viscous  residuum  of  any  desired  consistency  from  the 
distillation  of  oil  tars.  See  Chapter  V. 

Ozocerite.  A  yellow  or  brown  hydrocarbon,  greasy,  waxlike  substance, 
occurring  in  the  form  of  small  veins  in  tertiary  rock  in  Galacia,  Austria  and 
Utah,  U.  S.  A. 

Ozokerite.     Same  as  Ozocerite. 

Paraffin.  Commonly,  the  same  as  paraffine;  a  hard,  white,  wax-like  sub- 
stance, chemically  of  the  higher  hydrocarbons.  See  Chapter  V. 

Paraffine.  A  term  covering  a  number  of  greasy  crystalline  hydrocarbons  of 
the  paraffin  series. 

Paraffin  Naphtha.    Naphtha  from  paraffin  petroleum. 


420  APPENDIX  IV 

Paraffin  Oil.  A  heavy  liquid  fraction  of  the  manufacture  of  paraffin  from 
petroleum.  See  Chapter  V. 

Paraffin  Petroleum.  Petroleum,  the  base  of  which  is  principally  of  the  paraffin 
series  of  hydrocarbons. 

Paraffin  Scale.     Solid  paraffins  in  asphalt.     See  Chapter  V. 

Petrolene.  Those  portions  of  asphalt  and  similar  materials  which  are 
soluble  both  in  carbon  bisulphide  and  petrolic  ether,  and  which  are  volatile  at 
163  deg.  Cent,  and  below. 

Petroleums.  Native  mineral  oils  or  fluid  native  bitumens  of  variable  com- 
position. 

Petrolic  Ether.  A  volatile  naphtha  lighter  than  gasoline,  obtained  from 
petroleum. 

Pine  Oil.     A  heavy  distillate  of  rosin. 

Pine  Tar.  Gum  of  the  pine  tree  from  an  incision  or  by  distillation  of  the  wood ; 
common  rosin. 

Pipe  Coating.  A  bituminous  compound  applied  hot  or  cold  to  iron  or  steel 
pipes  for  preservation  purposes. 

Pitch.  A  sticky  resin  from  pine  tar.  Semi-solid  or  solid  residues  from  the 
distillation  of  bitumen;  usually  applied  to  residue  obtained  from  tar.  Short,  for 
coal-tar  pitch. 

Pitch  (Hard).     Pitch  showing  a  penetration  of  not  more  than  ten. 

Pitch  (Soft).     Pitch  showing  a  penetration  of  more  than  ten. 

Pitch  (Straight-run).*  A  pitch  run  in  the  initial  process  of  distillation,  to 
the  consistency  desired  without  Subsequent  fluxing. 

Plaster  Bond.  Name  of  various  bituminous  compounds  used  for  bonding 
plaster  to  masonry  walls,  and  which  also  serve  as  dampproofing  mediums. 

Plaster  of  Paris.  A  hydraulic  cement;  a  chalky  powder  resulting  from  the 
calcination  of  pure  gypsum  (a  hydrated  calcium  sulphate)  at  a  temperature 
between  250  and  400  deg.  Fahr.  losing  thereby  three-quarters  of  its  water  of 
combination. 

Plastic  Roofing.  A  plastic  (when  warm)  roofing  compound  applied 'with  a 
trowel,  composed  of  some  fine  or  fibrous  inert  substance  mixed  with  tar  or  other 
bitumen. 

Plastic  Slate.     A  mixture  of  coal  tar  and  powdered  slate. 

Portland  Cement.  A  fine  cementing  powder  made  by  carefully  burning  and 
grinding  a  cement  rock  or  an  artificial  mixture  of  limestone  and  clay.  See  Chap- 
ter V. 

Primer.  A  first  coat  applied  to  masonry  preparatory  to  receiving  the  suc- 
cessive coats  of  material  for  waterproofing  or  dampproofing  purposes. 

Puzzolan  Cement.  A  very  fine  cementing  powder  made  by  mechanically 
mixing  and  powdering  slaked  lime  and  volcanic  ash  or  slag. 

Pyrobitumens.  Mineral  organic  substances  forming  bitumens  upon  being 
subjected  to  destructive  distillation. 

Pyrogenetic.     That  which  originates  from  the  action  of  heat. 

Quasi-colloidal  Bodies.     Like,  or  nearly  colloidal,  particles. 

Quasi-soap.     Like,  or  as  if  it  were,  soap. 

Red  Rope  Paper.  A  red  variety  of  building  paper  partly  composed  of  rope 
waste. 

Reduced  Oils.     Reduced  petroleums. 

*  Proposed  by  the  Committee  on  Standard  Test?  for  Road  Materials  (Committee  D-4) 
of  the  American  Society  for  Testing  Materials. 


GLOSSARY  OF  TERMS  USED  IN  WATERPROOFING        421 

Reduced  Petroleums.  Residual  oils  from  crude  petroleum  after  removal  of 
water  and  some  volatile  oils,  but  with  the  base  chemically  unaltered. 

Refined  Asphalt.  Bitumen  after  it  has  been  freed  wholly  or  in  part  from 
its  impurities. 

Refined  Tar.  A  tar  freed  from  water  by  evaporation  or  distillation  which 
is  continued  until  the  residue  is  of  desired  consistency  or  a  product  produced  by 
fluxing  tar  residium  with  tar  distillate. 

Residual  Oils.     Residual  petroleums. 

Residual  ^Petroleum.  Viscous  residue  from  the  distillation  of  crude  petroleum 
with  all  the  burning  oils  removed. 

Residual  Tars.  Tar  pitch  or  viscous  residue  from  the  distillation  of  crude 
tar  with  all  the  light  oils  removed. 

Resin.  A  dried  and  hardened  pitch  from  pine  and  similar  trees.  See  Chap- 
ter V. 

Rock  Asphalt.  A  solid  asphalt  obtained  from  a  naturally  impregnated 
limestone  or  sandstone,  also  the  naturally  impregnated  stone. 

Roofing  Cement.  A  plastic  mixture  of  paint  skins,  coal  tar,  pine  tar  and 
soya  oil  commonly  used  to  seal  flashing  joints. 

Roofing  Gravel.     Approximately  f-inch  gravel. 

Roofing  Slag.     Slag  crushed  to  the  size  ranging  between  \  and  Hnch. 

Rosin.     Pine  pitch  with  the  chemical  formula  C44H62O4.     See  Chapter  V. 

Salammoniac.  Ammonium  chloride;  a  white  crystalline  soluble  substance 
(NH4C1).  See  Chapter  V. 

Sand.  Finely  divided  rock  detritus  the  particles  of  which  will  pass  a  10-mesh 
and  be  retained  on  a  200-mesh  screen. 

Sand  Cement.  A  very  fine  cementing  powder  made  by  grinding  together 
a  mechanical  mixture  of  Portland  cement  and  pure,  clean  sand. 

Semi-asphaltic  Oils.     Semi-asphaltic  petroleum. 

Semi-asphaltic  Petroleum.     Petroleum  of  a  semi-asphaltic  base. 

Sheet  Mastic.  Bituminous  mastic  in  the  form  of  a  sheet  used  for  paving 
and  waterproofing  purposes.  See  Chapter  II. 

"  Short."     A  term  applied  to  materials  possessing  little  ductility. 

Soap.     A  metallic  salt  of  fatty  acid.     See  Chapter  V. 

Soda  Ash.  Washing  soda  (carbonate  of  lime)  of  the  chemical  formula 
(Na2C03,  10HaO). 

Soluble  Glass.     Water  glass. 

Stearate.     A  salt  of  stearic  acid.     See  Chapter  V. 

Stearic  Acid.  A  derivative  product  of  the  more  solid  fats  of  the  animal 
kingdom.  (CH3(CH2)16COOH).  See  Chapter  V. 

Stearin.     The  chief  ingredient  of  suet  and  tallow.     See  Chapter  V. 

Stearin  Pitch.  A  black,  elastic,  non-brittle,  animal  by-product  obtained  from 
stearic  acid  in  the  manufacture  of  candles.  See  Chapter  V. 

Subway  Asphalt.  Common  name  for  a  particular  quality  of  asphalt  used  in 
waterproofing  the  New  York  Subways.  See  Chapter  VIII. 

Subway  Pitch.  Common  name  for  a  straight-run  coal-tar  pitch  used  in 
waterproofing  subways  in  New  York  City.  See  Chapter  VIII  . 

Suet.  The  hard  and  semi-fusible  fat  about  the  kidneys  and  loins  of  animals. 
See  Chapter  V. 

Surface  Coating.  Any  compound  applied  to  a  masonry  surface  for  damp- 
proofing  or  waterproofing  purposes. 


422  APPENDIX  IV 

Sylvester  Process.  The  process  of  applying  alternate  coats  of  soap  and  alum 
solutions  for  waterproofing  and  dampproofing  purposes.  See  Chapter  II. 

Tar  Pitches.     Semi-solid  or  solid  residual  tars. 

Tar.  Bitumen  which  yields  pitch  upon  fractional  distillation  and  which  is 
produced  as  a  distillate  by  the  destructive  distillation  of  bitumens,  pyrobitumens, 
or  organic  material.  See  Chapter  V. 

Texene.    A  trade  name  for  a  turpentine  substitute. 

Torpedo  Gravel.     A  coarse  hard  grit. 

Trinidad  Asphalt.  A  solid  or  semi-solid  asphalt,  brown  to  black  in  color, 
porous  and  about  50  per  cent  impure,  obtained  from  the  island  of  Trinidad. 

Turrellite.     A  black,  hard  variety  of  bitumen. 

Vintaite.     Gilsonite. 

Varnish  Gum.  Any  resinous  substance  excluding  rosin.  A  term  used  to 
designate,  but  incorrectly  so,  asphalt  and  coal  tar  when  used  in  proprietary  water- 
proofing compounds. 

Viscosity.  The  measure  of  the  resistance  to  flow  of  a  bituminous  material, 
usually  stated  as  the  time  of  flow  of  a  given  quantity  of  the  material  through  a 
given  orifice. 

Volatile.  Applied  to  those  fractions  of  bituminous  materials  which  will 
evaporate  at  climatic  temperatures. 

Water  Absorbent.  A  property  of  a  floor-hardening  or  waterproofing  material 
which  makes  it  readily  miscible  with  water. 

Water  Glass.  Sodium  silicate  (Na.Si,O9)  or  alkaline  silicates  soluble  in 
water. 

Water  Repellent.  A  property  of  a  waterproofing  material  which  hinders 
or  prevents  its  miscibility  with  water. 

Water  Table.     Loosely  applied  to  ground -water  level. 

Waterproofing.  The  process  of  treating  masonry  to  exclude  or  prevent  the 
percolation  of  moisture  or  water  through  it. 

Water-gas  Tar.  A  liquid  hydrocarbon  produced  by  cracking  oil  vapors  in 
the  manufacture  of  carburetted  water-gas.  See  Chapter  V. 

Wurtzelite.    A  black,  hard  variety  of  bitumen. 


APPENDIX   V 
REFERENCES 

The  following  reference  literature  is  arranged  only  approximately  according 
to  the  caption  topics.  Most  of  this  literature  was  consulted  in  the  preparation  of 
this  book,  acknowledgments  being  made  in  foot-notes.  The  author  is  gratified 
to  note  the  increased  interest  manifested  in  waterproofing  engineering  since  the 
commencement  of  this  book,  four  years  ago,  and  the  broader  viewpoint  assumed 
by  writers  of  modern  literature  on  the  art  of  waterproofing. 

Asphalt  and  Tar. 

Richardson's  Modern  Asphalt  Pavement. 

Bituminous  Road  and  Paving  Materials,  by  Hubbard. 

The  Art  of  Roadmaking,  by  Harwood  Frost. 

Effect  of  Illuminating  Gas  on  Asphalt  Pavements,  Eng.  News,  Mar.  4,  19LK, 
Vol.  73,  No.  9,  p.  441. 

Waterproofing,  by  Boorman,  Proceedings  National  Association  of  Cement 
Users,  1909. 

Coke-oven  Tars  of  the  United  States.  Office  of  Public  Roads,  Circular  No. 
97,  U.  S.  Dept.  Agriculture,  1912. 

Concrete  in  General. 

Concrete,  Plain  and  Reinforced,  by  Taylor  and  Thompson. 

Concrete,  Plain  and  Reinforced,  by  Homer  A.  Reid. 

Reinforced  Concrete,  by  Buel  and  Hill. 

Cairn's  "  Cement  and  Concrete." 

Reinforced  Concrete,  by  Marsh. 

Oil-mixed  Portland  Cement  Concrete,  Bulletin  No.  230,  Office  of  Public 
Roads,  U.  S.  Dept.  of  Agriculture,  1915. 

Concrete  in  Sea  Water. 

The  effect  of  SO3  in  Portland  Cement.  Proceedings  of  Association  of  German 
Portland  Cement  Manufacturers,  1911. 

"  Action  of  Sea  Water  on  Hydraulic  Binding  Media,"  by  Lombard  and 
Deforge,  International  Association  for  Testing  Materials  Proceedings,  1912. 

"  Action  of  Sea  Water  on  Reinforced  Concrete,"  by  de  Blocq  van  Kuffeler, 
International  Association  for  Testing  Materials  Proceedings,  1912. 

"  The  Different  Iron  and  Slag  Cements,"  Engineering  News,  September  7, 
1911,  Vol.  66,  No.  10,  Editorial. 

"  Ferrite  Cement  and  Ferro  Portland  Cement,"  by  E.  C.  Eckel,  Engineering 
News,  Aug.  3,  1911,  Vol.  66,  No.  5. 

"The  State  of  Preservation  of  Test  Blocks,"  by  W.  Czarnowski.  Inter- 
national Association  for  Testing  Materials,  1912. 

423 


424  APPENDIX  V 

"  Cement  in  Sea  Water,"  by  A.  Poulson.  International  Association  for  Test- 
ing Materials,  1909. 

"  Official  German  Recognition  of  the  Harmless  Nature  of  a  Slag  Addition  to 
Portland  Cement  Clinker."  Engineering  News,  September  7,  1911. 

"  Experiments  on  the  Decomposition  of  Mortars  by  Sulphate  Waters,"  by 
G.  A.  Bied.  International  Association  for  Testing  Materials,  1909. 

"  Some  Observations  on  the  Disintegration  of  Cinder  Concrete,"  by  George 
Borrowman.  Journal  of  Industrial  and  Engineering  Chemistry,  June,  1912. 

"  Disintegration  of  Fresh  Cement  Floor  Surfaces,"  by  Alfred  H.  White, 
American  Society  for  Testing  Materials,  Vol.  9. 

Relative  Effects  of  Frost  and  Sulphate  of  Soda  Effloresence  Tests  on  Build- 
ing Stones.  Transactions  of  the  American  Society  of  Civil  Engineers,  Vol.  33, 
1895. 

Action  of  the  Salts  in  Alkali  Water  and  Sea  Water  on  Cements.  U  S.  Bureau 
of  Standards,  Bulletin  No.  12,  Nov.,  1912. 

Action  of  Sea-water  on  Mortar.     Cement  Age,  March,  1907. 

Destruction  of  Cement  Mortar  and  Concrete  by  Alkali  at  Great  Falls,  Mont. 
Eng.  Cont.,  June  24,  1908. 

Durability  of  Stucco  and  Plaster  Construction.  U.  S.  Bureau  of  Standards 
Bulletin  No.  70,  Jan.,  1917. 

What  is  the  Trouble  with  Concrete  in  Sea  Water?  Engineering  News-Record, 
Vol.  79,  No.  12,  page  532. 

Dampproofing. 

The  prevention  of  Dampness  in  Houses,  by  A.  F.  Keim. 

Electrolysis. 

Electrolysis  in  Concrete;  Tech.  Paper  No.  18,  Bureau  of  Standards,  U.  S. 
Dept,  of  Commerce,  1913. 

Surface  Insulation  of  Pipes  as  a  Means  of  Preventing  Electrolysis.  Tech. 
Paper  No.  15,  Bureau  of  Standards,  U.  S.  Dept.  of  Commerce,  1914. 

Special  Studies  in  Electrolysis  Mitigation,  Tech.  Paper  No.  32,  Bureau  of 
Standards,  U.  S.  Dept.  of  Commerce  19 

Engineering  Structures. 

Waterproofing — An  Engineering  Problem,  by  Myron  H.  Lewis.  Proc. 
Engrs.  Club  of  Phila.,.  Vol.  25,  page  339,  Oct.,  1908. 

Waterproofing,  Progress  Report  of  Special  Committee  on  Concrete  and  Rein- 
forced Concrete.  Trans.  Am.  Soc.  C.  E.,  Vol.  66,  page  444,  March,  1910. 

Waterproofing  Cement  Mortars  and  Concretes,  by  H.  Wiederhold.  Proc. 
Natl.  Assoc.  Cement  Users,  Vol.  3,  page  228,  1907. 

Waterproofing  Cement  Mortars  and  Concretes,  by  Edward  W.  De  Knight. 
Proc.  Natl.  Assoc.  Cement  Users,  Vol.  3,  page  238,  1907. 

Waterproofing  Concrete  and  Masonry,  by  Edward  W.  De  Knight,  Eng.  News, 
Vol.  57,  page  187,  Feb.  14,  1907. 

Waterproofing  Cement  Structures,  by  James  L.  Davis,  Proc.  Natl.  Assoc. 
Cement  Users,  Vol.  4,  page  323,  1908. 

Waterproofing  of  Concrete  Structures,  pages  344-74.  Hand-book  for  Cement 
and  Concrete  Users,  by  Lewis  and  Chandler. 

Making  Concrete  Waterproof,  by  Prof.  I.  O.  Baker,  Eng.  News,  Vol.  62,  page 
390,  Oct.  7,  1909. 


REFERENCES  425 

Waterproofing  of  Engineering  Structures,  by  W.  H.  Finley,  Journal  Western 
Society  of  Engineers,  June,  1912. 

The  Waterproofing  of  Solid  Steel  Floor  R.R.  Bridges,  Am.  Society  Civil  Engrs., 
Vol.  40,  No.  10,  Dec.,  1914. 

Report  of  Committee  VIII  on  Masonry,  Proceedings  Am.  Railway  Engineer- 
ing Association,  Vol.  15,  page  569,  March,  1914. 

Review  of  Various  Experiences  in  Waterproofing.     "  Concrete,"  April,  1916. 

"  Engineering  Geology,"  by  Heinrich  Reis  and  Thomas  L.  Watson. 

The  Manufacture  of  Coke  in  the  United  States.  U.  S.  Geologic  Survey 
Bulletin,  Dept.  of  Interior,  1913.  , 

Formulas  and  Recipes. 

Henley's  20th  Century  Book  of  Formulas  and  Recipes. 

"  Paint  Making  and  Color  Grinding,"  by  Charles  S.  Uebele. 

General  Literature  on  Waterproofing. 

"  Masonry  Construction,"  by  Ira  O.  Baker. 

"  Building  Construction,"  by  Prof.  Henry  Adams. 

Merriman's  "  Civil  Engineer's  Pocketbook." 

Subways  and  Tunnels  of  New  York,  by  Gilbert,  Wightman  and  Saunders. 
•^      Panama  Canal  Waterproofing,  Engineering  News,  Vol.  73,  No.  5,  page  215, 
Feb.  4,  1915. 

Treatise  on  Arches,  by  Scheffler. 
+     Impermeable  Water  Tanks,  Eng.  News,  Mar.  18,  1914,  Vol.  71. 

Grouting. 

"  Lining  Rondout  Pressure  Tunnel,"  New  York,  Engineering  Record,  Dec. 
30,  1911,  page  772. 

Grouting  Big  Savage  Tunnel,  Using  Air,  Eng.  Rec..  page  728,  Dec.  23,  1911. 

Olive  Bridge  Dam,  New  York,  Eng.  Rec.,  page  385,  April  8,  1911. 

Rondout  Pressure  Tunnel,  New  York,  Eng.  Rec.,  page  315,  Sept,  17,  1910. 

Grouting  Arches,  Hamburg,  Germany,  Eng.  Rec.,  page  258,  Sept.  3,  1910. 

French  Methods  and  Machines,  Eng.  Rec.,  page  495,  Oct.  30,  1909. 

Foundations  in  England,  Eng.  Rec.,  page  474,  April  4,  1908. 

Stopping  Leaks,  Cincinnati  Water  Works,  Eng.  Rec.,  page  224,  Mar.  4,  1905. 

"  Grouting  a  Water-bearing  Rock  Seam  on  Catskill  Aqueduct,"  Eng.  News, 
Vol.  67,  No.  6,  page  278,  Feb.  8,  1912. 

Test  of  Watertightness  of  Concrete  Tunnel  Lining  under  High  Head,  Eng. 
News,  Vol.  66;  No.  24,  page  710,  Dec.  14,  1911. 

Mixing  and  Conveying  Concrete  by  Compressed  Air,  Eng.  News,  Vol.  66,  No. 
6,  page  173,  Aug.  10,  1911. 

Rondout  Pressure  Tunnel,  New  York,  Eng.  News,  Vol.  65,  No.  22,  page  654, 
Junel,  1911. 

Lining  and  Grouting  a  French  Railway  Tunnel  in  Water-bearing  Material, 
Eng.  News,  Vol.  62,  page  580,  Nov.  25,  1909. 

Pumping  of  Cement  Grout  into  Masonry  on  the  Metropolitan  Railway,  Paris, 
Eng.  News,  Vol.  62,  page  581,  Nov.  25,  1909. 

Grouting  a  Leaky  Tunnel  on  the  Paris,  Lyons  and  Mediterranean  Railway, 
Eng.  News,  Vol.  56,  No.  15,  page  374,  Oct.  I'l,  1906. 

"  Catskill  Aqueduct,"  by  Lazarus  White. 


426  APPENDIX  V 

Inspection. 

Inspection  of  Waterproofing  for  Concrete  Work,  by  Jerome  Cochran,  Engr. 
and  Contr.,  Vol.  37,  pages  370  and  404,  April  3  and  103  1912. 

Joints. 

Effect  of  Oil  on  Cement  Mortar,  Eng.  News,  July  4,  1907,  Vol.  58,  No.  1. 

Efficiency  of  Cement  Joints  in  Joining  Old  Concrete  to  New,  Eng.  News, 
Dec.  12,  1907,  Vol.  58,  No.  24. 

Strength  of  Concrete  Joints,  Proceedings  of  Engineer's  Society  of  Western 
Penn.,  Dec.,  1908. 

Lime,  Hydrated  Lime  and  Clay. 

"  Hydrated  Lime,"  by  E.  W.  Lazell,  Ph.  D.  (1915). 

The  Colloid  Matter  of  Clay  and  its  Measurement.  Bulletin  No.  388,  U.  S. 
Geol.  Survey,  Dept.  of  Interior,  1909. 

Lime:  Its  Properties  and  Uses;  Circular  No.  30,  Bureau  of  Standards, 
U.  S.  Dept,  of  Commerce,  1911. 

Metal  Sheetings. 

"  Harlem  River  Crossing  of  the  Lexington  Ave.  Subway."  New  York  Muni- 
cipal Eng.  Journal,  Vol.  1,  No.  6,  Dec.,  1915. 

Methods  of  Waterproofing. 

Methods  of  Waterproofing  Concrete,  by  Richard  H.  Gaines,  Eng.  News, 
Vol.  58,  No.  13,  page  344,  Sept.  26,  1907. 

Current  Methods  of  Waterproofing  Concrete-covered  Bridge  Floors,  Eng. 
Rec.,  Vol.  58,  page  488,  Oct.  31,  1908. 

Waterproofing  the  New  York  Subways,  Railway  Review,  Vol.  58,  No.  11, 
March,  1916. 

Subaqueous  Highway  Tunnels,  American  Society  C.  E.,  Vol.  4,  No.  9,  Nov.> 
1914. 

Roofing. 

Inspector's  Pocket  Book,  by  A.  T.  Byrne. 

Building  Mechanics'  Ready  Reference,  by  H.  G.  Richey. 

Sand  and  Cement. 

Standard  Sand  for  Cement  Work,  Eng.  Rec.,  July  20,  1907. 

Sands:  Their  Relation  to  Mortar  and  Concrete,  Cement  Age,  July,  1908. 

A  Sand  Specification  and  its  Specific  Application,  Proc.  of  the  Amer.  Soc. 
for  Testing  Materials,  Vol.  10,  1910. 

The  Cement  Industry  in  the  United  States,  U.  S.  Geol.  Survey,  Dept.  of 
Interior,  Bulletin  for  1910. 

Brown's  "  Hand  Book  for  Cement  Users." 

Specifications. 

Specifications  Covering  Methods  of  Waterproofing  Engineering  Structures 
by  Joseph  N.  O'Brien,  Eng.  Contr.,  Vol.  34,  page  26,  July  13,  1910. 

Specifications  for  Obtaining  Dampproof  and  Waterproof  Substructures,  Eng. 
Contr.,  Vol.  34,  page  239,  1910. 

Specifications  and  Instructions  for  Waterproofing  Metal  and  Masonry 
Structures,  by  W.  H.  Finley,  Eng.  Contr.,  Vol.  30,  page  289,  Nov.  4,  1908, 

Specifications  for  Waterproofing  Concrete  Work,  by  W.  H.  'Finley,  Proc, 
Natl.  Assoc.  Cement  Users,  Vol.  1,  page  .35,  1905. 


REFERENCES  427 

Specifications  for  Waterproofing  Concrete  Bridges — Chicago  and  North- 
western Railway,  Proc.  Natl.  Assoc.  Cement  Users,  Vol.  1,  1905. 

Specifications  for  Waterproofing  Bridges  in  the  District  of  Columbia,  Proc. 
Natl.  Assoc.  Cement  Users,  Vol.  5,  page  146,  1909. 

Specifications  for  Waterproofing  a  Pumping  Chamber  in  Ground  under 
External  Head  of  Water,  Proc.  Natl.  Assoc.  Cement  Users,  Vol.  5,  1909. 

Specifications  for  Waterproofing  New  York  Rapid  Transit  Subway,  Proc. 
Natl.  Assoc.  Cement  Users,  Vol.  1909,  page  237. 

Specifications  for  Waterproofing  Solid  Steel-floor  R.R.  Bridges,  Eng.  Cont., 
Sept.,  1915. 

Tests. 

Methods  for  Testing  Coal  tar,  etc.,  by  S.  R.  Church,  Journal  of  Industrial 
and  Engineering  Chemistry,  Vol.  5,  No.  3,  1913. 

Specific  Gravity,  Its  Determination,  etc.,  by  J.  M.  Weiss,  Journal  of  Industrial 
and  Engineering  Chemistry,  Vol.  7,  No.  1,  1915. 

The  Permeability  of  Concrete  under  High  Water  Pressure,  Eng.  News, 
Vol.  47,  No.  26,  page  517,  June,  1902. 

Paraffin  Test  as  Applied  to  Bituminous  Road  Compounds,  Eng.  News,  July  8, 
1911,  Vol.  65,  page  680. 

Methods  for  the  Examination  of  Bituminous  Road  Materials,  Bulletin  No. 
314,  U.  S.  Dept.  of  Agriculture,  1915. 

Permeability  Tests  on  Gravel  Concrete,  Eng.  Rec.,  Sept.  26,  1914. 

Permeability  Tests  of  Concrete,  Eng.  Rec.,  Jan.  21,  1911. 

Test  of  Concrete  for  Impermeability,  Eng.  Rec.,  May  28,  1910. 

Impermeability  Tests  on  Concrete,  Eng.  News,  Nov.  7,  1912. 

Investigation  of  Impermeable  Concrete,  Eng.  Contr.,  Feb.  26,  1908. 

Progress  Report  on  Materials  for  Road  Construction  and  on  Standards  for 
Their  Tests  and  Use.  Amer.  Soc.  C.  E.,  Vol.  40,  No.  10,  Dec.,  1914. 

The  Testing  of  Materials.  Circular  No.  45,  U.  S.  Bureau  of  Standards, 
Dept.  of  Commerce,  1913. 

Some  Practical  and  Technical  Tests  on  Waterproofing  Materials,  N.  Y. 
Municipal  Engineers'  Journal,  Sept.,  1917. 

Waterproofing  Fabrics. 

Manufacture,  Test  and  Use  of  Waterproofing  Fabric,  Eng.  News,  Vol.  72, 
Sept.  24,  1914. 

The  Waterproofing  of  Fabrics  by  Mierzinski. 

Linen,  Jute  and  Hemp  Industries;  Special  Agents  Series  No.  74,  U.  S.  Dept. 
of  Commerce,  1913. 

Waterproofing  Instructions. 

Instructions  for  Waterproofing  Concrete  Surfaces,  by  W.  J.  Douglas,  Eng. 
News,  Vol.  56,  No.  25,  page  645,  Dec.  20,  1906. 

Directions  for  the  Application  of  Waterproof  Cement  Coatings,  Eng.  News, 
Vol.  57,  Jan.,  1907,  page  247. 

Suggestions  for  Waterproofing  Subways,  Public  Service  Record,  Vol.  3, 
No.  7,  July,  1916  (Publication  of  Public  Service  Commission  for  1st  District, 
State  of  New  York). 

Popular  Handbook  for  Cement  and  Concrete  Users,  by  M.  H.  Lewis,  C.  E. 

Waterproofing  Materials. 

Materials  of  Construction,  by  Thurston. 


INDEX 


Absorption,  Defined,  7 

—  of  Concrete,  4,  229,  230 
-  Raw  Fabrics,  256,  257 

—  Felts,  256,  257 

Stone,  4 

—  Treated  Felts,  256,  257 

Fabrics,  256,257 

Abutments,  Protection  of,  31 
Acid  Treatment,  21 

—  Sludge  Defined,  413 
Acids,  Effect  of,  29 

—  in  Ground  Water,  3 
Actinolite,  Use  of,  111 
Adhesion  between  Laps,  46 
Adhesives,  320 
Aggregate  for  Mastic,  63 

—  Defined,  413 

—  Scientific  Proportioning,  77 
Air  Compressor,  Use  of,  87 

-  Pockets,  23,  47 

—  Temperature,  28 
Akeley,  Mr.  C.  F.,  19 
Albertite  Defined,  413 
Alcohol,  Specific  Gravity,  387 
Alkalies,  Effect  of,  29 
Alkaline,  3 

Alum,  26,  145,  147,  374 

—  Defined,  413 

—  Nature  of,  147 

—  Solution,  28 

—  Use  of,  197 
Alumina,  9 
Aluminum  Sulphate,  28 

—  Stearate,  66 

Am.  Ry.  Engrs.  Assn.,  117,  129 

—  Soc.  T.  M.  Report,  408 
Anthracene  Defined,  413 
Arbitrary  Selection,  78 
Arches,  32 


Architect's  Duty,  25 
Armor  Coat,  58 
Asbestine  Defined,  413 
Asbestos,  23,  31,  374 

—  Covered  Roofing,  121 

-  Covered  Sheet  Iron,  120,  146 

-  Defined,  413 

—  Felt,  Application  of,  111 
—  Defined,  153,  413 

-  Saturated,  146 

-  Use  of,  45,  153 

—  Fibre,  Use  of,  63 

-  Filler,  Effect  of,  238,  240 

-  Nature  of,  153 

—  Shingles,  Application   of,    11,    101, 

102,  103 
Manufacture  of,  102 

—  Shredded,  32 

—  Specific  Gravity,  387 

-  Use  of,  56,  153 

Ash  Water  Glass  Defined,  413 
Asphalt,  32,  145,  146,  147,  374 

-  Blown,  Use  of,  141 

—  Cement  Defined,  413 

—  Characteristics  of,  51 

—  Coefficient  of  Expansion,  387 

—  Containing  Pitch,  240 

—  Consistency  of,  49 

-  Cutter,  178,  179 

-  Defined,  413 

—  Ductility  of,  240 

—  Effect  of  Overheating,  49 

—  Heating  Kettle,  175,  174 
of,  49 

—  Joint  Filler,  142 

-  Mastic  Defined,  413 

—  Nature  of,  154 

—  Odor  of,  49 

—  Pavement  Defined,  413 
—  Preference  for,  52 


430 


INDEX 


Asphalt,  Produced,  51 

—  Publications  on,  423 

—  Putty  Defined,  413 

—  Quality  of,  51 

—  Smoother,  177 

—  Specific  Gravity,  387 

-  Use  of,  17,  31,  32,  154 

—  Versus  Coal-tar  Pitch,  51 
Asphaltenes  Defined,  413 
Asphaltic  Coal,  414 

—  Concrete,  414 

-  Defined,  413 

—  Limestone  Defined,  414 

—  Oils  Defined,  414 

—  Petroleum  Defined,  414 

—  Sandstone  Defined,  414 
Asphaltite  Defined,  414 
Asphaltum  Defined,  414 

B 

Backfill,  13,  39,  40 
Bacterial  Decomposition,  8 
Bakelite,  146,  147,  414 

-  Use  of,  154 
Bank-run  Gravel,  78,  414 
Barrels,  Cost  of,  373 
Barret  Specification  Felt,  414 
Basement  Waterproofed,  365 
Bats,  Use  of,  56 

Battens,  Use  of,  114 

Baume  Table,  381,  382,  383,  384,  385 

—  Gravity,  414 

Beeswax  Specific  Gravity,  387 

—  Coefficient  of  Expansion,  287 
Benzene  Defined,  414 
Benzine,  145,  147 

—  Cost  of,  374 

-  Defined,  414 

-  Use  of,  155 
Benzol,  Cost  of,  374 

—  Defined,  414 

-  Use  of,  155 

Bergen  Hill  Tunnels,  335,  336 
Bermudez  Asphalt  Defined,  414 
Binder,  32,  414 
Bitumen,  Artificial  Defined,  413 

—  Defined,  414 

—  for  Mastic,  62 

—  Ready  Roofing,  112 
• —  Transportation,  50 


Bituminous  Binder,  34 

—  Blanket,  31 

—  Cement  Defined,  414 

—  Coat  Applied,  24' 

—  Compound,  Use  of,  16,  29,  46,  146 

-  Defined,  414 

—  Emulsion  Defined,  414 

-  Enamels,  29 

-  Fillers,  142 

—  Mastic,  29,  52 

-  Paint,  18,  29,  142,  147,  155,  414 

-  Paste,  29,  31 

-  Putty  Defined,  414 

—  Rock  Defined,  414 
Bleeders,  Use  of,  58 
Blistering,  20,  26 
Block  Tin,  Use  of,  108 
Blow  H61es,  34 

Blown  Asphalt,  Use  of,  143,  414 

—  Oil  Defined,  414 

—  Petroleum  Defined,  414 
Board  Sheathing,  308 
Bond,  Effect  of  Surface,  249 
Bonding  Fabrics,  47 

-  Day's  Work,  70 
Boston  Tunnels,  337,  338 
Brick,  Absorption  of,  4 

—  Applied,  56 

-  Bond,  249 

—  Compression  of,  249,  250 

—  Cost  of,  374 

—  Courses,  57 

—  Function  of,  56 

-  Heating  Methods,  65,  66,  183,  373 

-  in  Mastic,  52,  53,  54,  56,  57,  63,  146, 

355 

-  Parapet,  118 

—  Protective  Medium,  37 

—  Quality  of,  61,  63 

—  Roof  Domes,  92 

—  Sewers,  20 

—  Soot  Covered,  65 

—  Specific  Gravity,  4,  387 

-  Walls,  58 
Bridge  Floors,  67 

—  Waterproofed,  53 
Bronze  Plate  Roofs,  92 
Brooklyn  Railroad  Viaducts,  34 
Broom,  Cost  of,  373 
Bubbles  in  Mastic,  62 


INDEX 


431 


Buckets,  Use  of,  50 
Building  Foundations,  32 

—  Paper  Denned,  414 

Built-up  Roofs,  92,  108,  308,  310,  415 

Membrane,  31,  45 

Bulge  in  Mastic,  61 
Burlap,  Use  of,  47,  155,  375 

—  Denned,  415 

-  Membrane,  Weight  of,  388 
Butt  Joints,  43 
Byerlite  Denned,  415 


Caffall  Process  Defined,  415 
Caisson  Cross-section,  292 
Calcium  Compounds,  9,  66,   75,   147, 
148,  415 

—  Minerals,  146,  147 

—  Oxide,  8 

—  Sulphate,  8 
Calking  Joints,  144 

-  Tunnels,  366 

Caoutchouc,  Specific  Gravity,  387 

—  Defined,  415 

Capillary  Passageways,  7,  19,  47 
Carbenes  Defined,  415 
Carbolineum,  93 
Carbon  Bisulphide,  Defined,  415 

—  Disulphide,  Defined,  415 

—  Tetrachloride,  Defined,  415 
Carborundum,  231,  415 
Casein,  Defined,  415 

-  Use  of,  148 

Cast-iron  Tunnel  Segments,  363 

—  Use  of,  146,  147,  156 
Cast  Steel,  146 

Castor  Oil,  Specific  Gravity,  387 
Catskill  Aqueduct,  87,  359 
Caustic  Potash,  145,  147,  148,  374 
Cedar,  Specific  Gravity,  387 
Cells  in  Concrete,  7 
Cement,  145,  375,  415 

—  Additions  to,  409 

—  Benzine  Resisting,  318 

—  Coating,  147 

—  Coefficient  of  Expansion,  387 

—  Effect  of  Alkali,  405,  407 
Fineness,  76,  77 

-  Water,  403,  407 
Wetting,  77 


Cement,  Excess,  77 

—  Floor  Defined,  415 

-  for  Mastic,  318 

—  Grouting,  85 

-Gun  Operation,    19,  20,  184,   185, 
186,  373 

—  Hydration  of,  77 

-  Mortar,  Use  of,  156,  16 

—  Petroleum  Resisting,  318 

—  Publications  on,  426 

—  Quick-setting,  85 

—  Specific  Gravity,  387 

-  Tiles,  97 
Cerasin  Defined,  415 
Cerite  Defined,  415 
Charcoal,  29 
Cheese,  Use  of,  144 

Chemical  Acting  Materials,  146,  147 
Chimneys,  Flashing  for,  117 
China  Clay,  72,  415 

-  Wood  Oil,  Defined,  415 

—  Specific  Gravity,  387 

-  Use  of,  31,  143,  148 
Chipping  of  Surface,  21 
Chloride  of  Lime,  74 
Choctow  Defined,  415 
Cinder,  Concrete  Absorption,  4 

—  Specific  Gravity,  4 
Cisterns,  24 

Civilization,  Measure  of,  2 
Clay,  66,  75,  415 

-  Oil-joint  Filler,  142 

—  Publications  on,  426 

—  Specific  Gravity,  387 

-  Tiles,  95,  96 

-Use  of,  26,  71,  72,91,  156 
Clay-cement  Waterproofing,  365 
Cleats,  Use  of,  108 
Climate,  Consideration  of,  31 
Clinker,  72 
Coal  Tar  Defined,  415 

-  Pit  Waterproofed,  366 
Coal-tar  Pitch,  32,  146,  147,  374 
Characteristics  of,  49,  51 

—  Defined,  415 

—  Joint,  Filler,  142 

—  Overheating,  49 

—  Produced,  51 

—  Versus  Asphalt,  51 
Products,  31,  75 


432 


INDEX 


Coal-tar  Pitch,  Use  of,  31,  49,  157,  164 
Coat  Defined,  415 
Coating  Continuous,  30 

—  on  Felts,  252,  253 

Fabrics,  252,  253 

Coatings,  Application  of,  21 

—  Applied  by  Brush,  19 

Machine,  19 

Trowel,  19 

—  Continuity  of,  19 

Coefficient  of  Expansion,  12,  124,  125 

of  Materials,  387 

Coke  Oven  Tar  Defined,  415 
Coking  of  Bitumen,  49 
Colloidal  Clay,  71,  146,  147 

—  Matter,  75,  415 
Colophony  Defined,  415 
Column  Bases  Waterproofed,  11 
Composite  Roofing,  120,  122 
Composition  Roofing,  92,  108 
Compounds,  Effect  of  Earth,  29 

^Backfill,  29 

Compressed  Asphalt  Defined,  416 
Compression  of  Brick,  249 

Mastic,  249 

Membrane,  260 

Mortar,  249 

Concrete,  374 

—  Absorption  of,  3,  4 

—  Additions  to,  409 

—  Age,  2 

—  Atomizer,  89,  90 

—  Average  Weight  of,  4 

—  Coefficient  of  Expansion,  387 

—  Consistencies,  78 

—  Cutoffs  for,  137 

—  Effect  of  Alkali,  405,  407 

—  Floor  Hardener,  319,  416 

—  Hand  Mixed,  77 

—  in  Sea  Water,  403,  406,  407 

—  Machine  Mixed,  77 

—  Parapet,  118 

—  Pipe  Joints,  137,  138 
Reinforcement,  82 

—  Porosity  of,  7,  77 

—  Primer  Defined,  416 

—  Protective  Coat,  37 

—  Publications  on,  423 

—  Railroad  Details,  343 

—  Reinforcement,  125 


Concrete  Roof  Slab,  310 

-  Roofs,  123 

—  Safeguarded,  9 

—  Specific  Gravity,  4,  387 

—  Standpipe,  331 

—  Tampers,  181,  182 

—  Tank  Waterproofed,  356 

-  Tile,  95,  96,  97,  98,  99,  100,  229,  230 

—  Time  of  Mixing,  99 

—  Universal  Material,  3 
Conglomerate,  Absorption  of,  4 

—  Specific  Gravity,  4 
Consistency  Defined,  415 
Construction  Joints,  14,  38,  128 
Efflorescence,  14 

—  Shaft,  83 

Contractors,  Graded,  370 
Copal  Gum,  ,72 
Coping,  117 

Copper  Bulb  Joint,  134 

-  Cutoffs,  134 

—  Sheeting,  105,  108 

—  Specific  Gravity,  387,  393 

—  V- Joints,  131 
Cord  Wood,  373 
Cores,  48 

-  Fabric  Roll,  182 

-  Felt  Roll,  182 

-  Illustrated,  183 
Corrosion,  2 

—  of  Metallic  Powders,  27 
Corrugated  Roofing,  121 

—  Sheet  Iron,  120,  393 
Corundum  Defined,  415 
Cost  Data,  371,  372 

-  Low  First,  145 

—  of  Materials,  374 

Implements,  373 

Labor,  372 

Tin,  378 

Waterproofing  Applied,  376,  377 

Cotton,  Drill,  Use  of,  34,  46,  48,  157, 
375,  416 

—  Fabric,  45,  46,  47 

—  Membrane,  388 

-  Roofing,  111,  120 
Cove  Finish,  53 
Cracked  Oil  Defined,  416 
Cracking,  20,  416 
Cracks,  Prevention  of,  125 


INDEX 


433 


Cracks,  Cause  of,  67 
Creosote,  93 

—  Oil,  Application  of,  31 
Crude  Tar  De  ined,  416 

—  Asphalt  Defined,  416 

—  Oil  Defined,  416 
Crumbling  Palisades,  8 
Cube  in  Air  Method,  198 

Water  Method,  198 

Curing,  26 

Cut-back  Pitch,  111 

Products  Defined,  416 

Cutoff,  Use  of,  134 

—  Wall,  17,  83,  85 
Cutters,  178,  373 
Cypress  Shingles,  92 

D 

Dam,  Ashokan,  Cutoff,  358 

—  Waterproofed,  325 
Dampproof,  13,  16 
Dampproofing  Compounds,  29,  314 

—  Defined,  416 

—  Publications,  424 

—  Walls,  16,  316 
Davit  Attachment,  174 
Day's  Work  Joint,  128 
Plane,  68 

Dead  Oil  Defined,  416 
Dehydrated  Tars,  Defined,  416 
Dense  Concrete,  77,  78,  80 
Density,  3 

—  Effect  of,  67 

—  Factors,  76 
Depressions  in  Surface,  33 
Design  Details,  81 

Destructive  Distillation  Defined,  416 
Development  of  Waterproofing,  1 
Dike  Form  Joint,  339 
Dipper,  167,  177,  373 
Dipping  Compound,  416 
Disintegrating  Effect,  2,  8,  26 
Drain  Pipes,  6 
Drainage,  5,  6,  134 

—  Defined,  416 

—  System,  33,  349 

Drop  Point  Apparatus,  207,  208 
Dry  Spots,  34 

—  Ply,  33,  54,  58 

—  Surface,  26,  33 


Drying,  26 

—  Oven,  214 

Dual  Subways  in  N.  Y.  C.,  54 
Ductility  of  Asphalt,  240  . 

—  Relation  to  Temperature,  246 
Dust  Defined,  416 
Dwellings,  Concrete,  2 

E 

Earth  Excavation,  58 
East  View  Tunnels,  331 
Eastern  Petroleum  Defined,  416 
Efflorescence,  6,  12,  14 
Egyptians  Practice  Waterproofing,  1 
Elastic  Membrane,  31,  45 
Elaterite,  Use  of,  145,  147,  157 
-  Defined,  416 
Electric  Oven,  213,  373 

—  Resistance,  10 
Electricity,  Effect  of,  9 
Electrolysis,  4,  9,  10 

—  Publications,  424 
Emulsion  Defined,  416 
Enamels,  145 

Engineering  and  Contracting,  8,  369 
Engineering  News,  325,  328,  334,  337 
Engineering  News-Record,  85,  322 
Engineering  Record,  337,  352 
Equipment  for  Grouting,  86 
Estimates,  368,  369 
Evaporating  Oven,  214 
Examples  of  Membrane  Application,  331 

Grouting,  357 

Integral  Application,  356 

Mastic  Application,  353 

Self-densification,  356 

Special  Waterproofing,  360 

Excavating  Foundations,  29 
Excess  Cement,  26,  70 
Expansion  Joint,  Basic  Types,  129 
-  Cutoff,  136 

Defined,  416 

Design  of,  126 

Drain  Pipe,  138 

Effect  of,  12 

Fillers,  129 

Function  of,  124 

Illustrated,  130 

Properties  of,  124,  128 

Reinforced,  135 


434 


INDEX 


Expansion  Joint,  Sliding,  138,  139 
—  Spacing  of,  126 

Waterproofed,  135 

Expansive  Force  of  Freezing  Water,  7 

Concrete,  7 

Exterior  Applications,  29 
External  Cutoffs,  134,  139 
—  Treatments,  410,  411,  412 
Exudation  of  Lime  Salts,  15 


Fabrics,  34,  48,  146,  374,  416 

—  Membrane,  52 

Fats,  Specific  Gravity,  387 

Fattening  Materials,  146 

Feldspar,  66,  71 

Felt  Joint  Protection,  132 

Felts,  32,  34,  46,  47,  48,  146,  158 

—  Cost  of,  374 

—  Defined,  416 

—  Flashing,   119 

—  Membrane,  31,  52,  388 

—  Roofing,  92,   108,   109 

—  Weight  of,  379 
Ferrules,  Use  of,  349 
Fillers,  Analysis  of,  72,  73 

—  Defined,  416 

—  Use  of,  62,  66,  72 
Film,  Continuous,  30 
Finial  Tiles,  98,  99 
Finishing  Coat  Applied,  22 
Fire  in  Kettles,  50 

—  Wall  Flashing,  16 
Fireproof  Liquids,  93 
Fireproofing,  16 
Fish-oil,  Use  of,  72,  75 
Fissured  Rock  Solidified,  83 
Fixed  Carbon  Defined,  416 
Flashing,  116,  117,  118,  416 
Flat  Roof,  92,  110 

—  Seam  Roofing,  106,  108 
Floating  Defined,  417 

—  Mortar  Surface,  20 
Floats,  182,  183 
Flood  Water,  5 
Floor  Joint  Filler,  144 

—  Hardener,  27,  231,  232,  233 
-—  Treatments,  319 

—  Waterproofing,  53 
Flow  Point  Apparatus,  209 


Flux  Defined,  417 

Foreign  Substances,  Addition  of,  67, 409 
Foreman  of  Waterproofers,  372 
Forms  for  Post  Holes,  56 

—  Armor  Coat,  59 
—  Bracing,   60 

—  Filling,    59,   61 

—  Setting  up,  59 
Formulas,  Special,  313 

—  Publications  on,  425 
Foundation  of  Pyramids,  1 

-Walls,  29 

Frea's  Electric  Oven,  213 
Free  Carbon,  214,  215,  216 

-  Defined,  417 

Freezing  Effect  of  Water,  2,  7 
Fuel  Material,  29,  50 
Fullers'  Earth,  80,  417 
Functional  Roofing,  92,  120,  123 
Fundamental  Waterproofing  Require- 
ments, 33 
Fumes,  49 
Furring  Compounds,  417 


Gable  Roofs,  92 
Gas  Black,  417 

—  Drip,  36,  417 

-  House  Coal-tar,  417 

-  Main,  Effect  of  Leaks,  36 

-  Oven,  214 
Gaskets,  Use  of,  129 

Gasoline,  31,  57,  147,  158,  374,  417 

-  Torch,  33,  178 
Gauging  Water,  417 
Gelatinous  Compound,  75,  146 
General  Electric  Method,  198,  205,  206 
German  Wax  Defined,  417 
Gilsonite,  Defined,  413,  417 

-  Use  of,  143,  147,  159.  374 
Glance  Pitch  Defined,  417 
Glass  Roofing,  120,  122 

—  Specific  Gravity,  387 
Glossary  of  Terms,  413 
Gooch  Crucible,  193 
Government  Publications,  313 
Grading,  Laws  of,  67,  80 
Grahamite,  Defined,  417 

-  Use  of,  147,  159 
Granite,  Absorption,  4 


INDEX 


435 


Granite,  Specific  Gravity,  4,  387 
Granolithic  Finish,  20,  24 
Graphite,  Defined,  417 
—  Specific  Gravity,  387 

-  Use  of,  146,  147,  159,  375 
Gravel  Concrete,  78 

—  Absorption,  4 

-  Defined,  417 

-  Heater,  175,  181 

—  Roof  Covering,  109 

—  Specific  Gravity,  4,  147,  375 

-  Use  of,  159 
Grit  Defined,  417 

Ground  Water,  Depth  of,  2,  5,  52 

-  Defined,  417 

—  Effect  on  Concrete,  5 

-  Fabric,  255 
Grout,  82,  145,  147,  417 
Grouting  Machine,  186,  187,  373 

—  Materials,  146 

-  Process,  17,  82,  84,  87..  88,  359,  417 
—  Publications,  425 

Gum  Defined,  417 

Gumlac  Defined,  417 

Gunite  Defined,  417 

Gutta  Percha,  Specific  Gravity,  387 

-  Defined,  417 
Gutters,  118,  120 

Gypsum,  Specific  Gravity,  387 

-  Defined,  417 

H 

Hail,  5 

Hair  Checks,  26 

Hard  Soap,  28 

Harlem  River  Tunnels,  360,  361 

Harris,  Mr.  Robert  L.,  83 

Headers,  61 

Heat,  Effect  on  Pitch,  236 

-  Linseed  Oil,  236 
Heating  Kettles,  50,  170,  171,  173 

-  Pan,  178,  180 
High  Carbon  Tars,  418 
Horizontal  Joints,  128 
Hot  Stuff  Defined,  128 
Hudson-Manhattan  Tunnels,  330,  365 
Hydrated  Lime,  66,  67,  146,  147,  375, 

426 

Composition,  71,  418 

Proportion,  70 


Hydrated  Lime,  Specific  Gravity,  7,  83 

-  Use  of,  69,  148 
—  Magnesia,  9 
Hydration  of  Mortar,  20 
Hydrocarbons,  23,  145,  418 
Hydrochloric  acid.  72 
Hydrogen  Sulphide,  8 
Hydrolitic  Defined,  418 
Hydrolithic  Defined,  418 
Hydrostatic  Head,  5,  36 
Hydrex  Compound,  418 
Hygienic  Effect  of  Waterproofing,  13 


Ice,  Specific  Gravity,  387 
Ideal  Mix,  80 
Imitatite  Defined,  418 
Immutability  Test,  260 
Impervious  Roofing,  93,  94,  118 

—  Coatings,  19 
Imperviousness  Essential,  81 
Implements,  Sundry,  166,  176 
Impsomite  Defined,  418 
Inert  Fillers,  23,  70,  71 
Inspection  of  Waterproofing,  372,  426 
Integral  Liquids,   15,   25,  28,   74,  75, 

418 

—  System,  Materials  for,  69,  146 

-  Purpose  of,  17,  66,  67,  68,  418 
Interior  Applications,  29 
Internal  Cutoffs,  134,  137 
Iron  Borings,  Use  of,  143 

-  Cutoffs,  134 

-  Oxide,  27 

-Powdered,  Use  of,   146,  147,    149, 
375,  418 

—  Sheeting  Thickness,  394 

—  Specific  Gravity,  387,  393 
Isinglass  Defined,  418 


Joining  Membranes,  34 
Joint  Baffle,  131 

-  Barrier,  133 

-  Fillers,  140,  141,  142,  426 
Chemical  Acting,  143 

-  Defined,  418 

-  Rolls,  129,  131 
Joints,  Effect  of,  42,  43 
—  for  Bridges,  133 


436 


INDEX 


Joints,  Effect  of,  Abutments,  133 

—  in  Brick  Masonry,  126 

Concrete,  62 

Forms,  61 

Membrane,  34 

Jute  Fabric,  Use  of,  46, 47, 48,  111,  160 

K 

Kalinite,  147 
Kaolin  Defined,  418 
Kauri  Gum,  72 
Kerosene,  29 
Kettlemen,  372 
Kettles,  50,  54,  179,  373 
Knot  Hole  Fillers,  144 

—  —  Care  of,  114 
Knowledge  of  Materials,  2 
Kraemer  &  Sarnow  Method,  198 


Labor,  27,  146,  370,  372 
Lake  Pitch  Defined,  418 
Land  Pitch  Defined,  418 

—  Plaster  Defined,  418 
Lap,  Cement,  418 

—  Sealed,  46 

—  Width  of,  34 
Larutan  System,  418 
Layer,  Defined,  418 

• —  Type  of  Membrane,  41 
Leaching,  Effect  of,  141 
Lead  Cutoffs,  134 

—  Sheet,  Use  of,  92,  365 

—  Sheet  Thickness  of,  393,  394 

—  Specific  Gravity,  387,  393,  394 

—  Wool,  Use  of,  144,  375 
Leaks,  Occurrence  of,  110 
Lean  Mixtures,  20 

—  Mortars,  25 

Lime,  19,  75,  145,  149,  375,  418 

—  Specific  Gravity,  387 

—  Stearate,  66 

—  Washes,  61 
Limestone,  Absorption,  4 

—  Dust,  62,  375 

—  Specific  Gravity,  4,  387 
Linseed  Oil,  93,  145,  147,  375,  418 

and  Pitch,  236,  237,  238 

Specific  Gravity,  387 


Linseed  Oil,  Paints,  18 

-  —  Use  of,  31,  149,  143 
Literature  on  Waterproofing,  1,  426 
Lithocarbon  Defined,  418 
Long  Island  Railroad  Subway,  332 
Low  Carbon  Tars,  418 
Lubricant  Action,  69 
Lubricants,  Function  of,  67 
Lubricating  Oil,  36 
Lye,  Concentrated,  28 

M 

Mabery-Sieplein  Method,.198,  202,  203 
Machinery,  166 
Magnesium  Chloride,  9 

—  Oxide,  8 

—  Sulphate,  3,  8,  9 
Maltha  Defined,  418 
Malthene  Defined,  419 
Manhattan-Bronx  Subway,  333 
Manhattan  Railroad  Viaducts,  341 
Manhole,  20 

Marble,  Absorption,  4 

—  Specific  Gravity,  4 
Martin's  Creek  Viaduct,  339 
Masonry,  Specific  Gravity,  387 

-  Solidified,  83 

—  Treatments,  314 
Mastic  Bond,  249 

-  Defined,  419 

—  Heating  Kettle,  64,  175 

—  Joint  Filler,  142 

-  Materials,  53,  62,  168 

-  Mixing  Kettles,  64,  65, 166, 167, 168, 

169,  170,  373 

—  Properties,  242,  247 

—  Roof  Flashing,  142 

—  Sheet,  52,  53,  54,  56 

—  Stirrers,  177 

—  System  of  Waterproofing,  17,  52 

—  Trowel,  183 

-  Use  of,  57,  63,  64,  145,  147,  161 

—  Volume,  62,  248,  390,  391 

—  Wall,  61 

-  Weight,  390,  391 

Mat,  Expansion  Joint,  139 
Materials  for  Calking,  143 

Grouting,  85 

Manjak  Defined,  419 
Meandering  Cracks,  127 


INDEX 


437 


Mechanical  Acting  Materials,  146,  147 
153 

—  Analysis,  80,  399 

Melting  Point  Methods,  197,  235,  236 
Membrane,  Application  of,  32,  40,  42, 
47 

—  Continuity,  33,  34,  40,  41 

—  Defined,   419 

—  Materials,  146 

—  Mats,  34,  42 

—  Protection  of,  34,  35,  36,  37 

—  Reinforcement,  46 

—  Sheet  Lead,  37 

—  System   of  Waterproofing,    17,   31, 

419 

Mesh  Joint,  34 
Metal  Flashing,  101,  107,  117 

-  Linings,  31,  33 

—  Primer  Defined,  419 

—  Shingles,  120 
Metallic  Compounds,  23 
Metals,  146,  426 
Mineral  Aggregate,  62,  146 

-  Fillers,  32 

—  Matter,  143 

-  Naphtha,  419 

—  Oil,  419 

-  Pitch,  419 

-  Rubber,  419 

—  Surfacing,  100 

—  Tar,  419 

-  Wax,  419 
Minwax  Defined,  419 
Missouri  Clay,  71 
Mixing  Methods,  5,  81 
Mixtures  of  Soap  and  Alum,  23 
Modulus  of  Elasticity,  12,  125 
Moisture  Absorption,  15 
Monolithic  Construction,  125 
Mops,  176,  373 

Mortar,  23,  25,  26,  82 

—  Defined,  419 

—  Joints,  126,  127 

—  Porosity  of,  27,  77 

-  Protective  Coat,  18,  37,  38 

—  Specific  Gravity,  387 

—  Tiles,  95 

—  Trowel,  183 
Muriatic  Acid  Applied,  21 
Mushy  Concrete,  78 


N 

Nailheads  Covered,  101 
Nailing  Base,  94 
Nails,  Use  of,  93,  101,  397 
Naphtha,  Coal-tar,  23 

—  Defined,  419 

-  Use  of,  31,  145,  147,  161 
Naphthaline  Defined,  419 
Natural  Asphalt,  146 

—  Cement,  72,  146,  147,  149,  419 
Native  Bitumen,  419 

-  Paraffin,  419 

Neat  Cement,  82,  145,  146,  147,  150 
Necessity  of  Waterproofing,  1 
Neponsit  Felt  Defined,  419 
Neutral  Oil  Defined,  419 
New  York  Board  of  Water  Supply,  86 

Clay,  71 

-  Dual  Subways,  334,  353 

Municipal  Railway  Corp,  343 

—  Testing  Laboratory  Method,  198, 
201 


Oak,  Specific  Gravity,  387 
Oil  Asphalts  Defined,  419 

—  Compounds,  66 
-  Effect  of,  36 

—  Emulsion,  74 

—  Gas  Tar  Defined,  419 

—  Specific  Gravity,  387 

—  Tester,  192 

Oil-tar  Pitch,  146,  147,  161,  375,  419 
Old  Laps,  34 
Oleate  Pctassium,  66 

—  Sodium,  66 

Oxidation  of  Reinforcement,  9 
Ozokerite  Defined,  419 
Ozocerite  Defined,  419 


Paddle  Mixing  Machine,  86 
Pails  Pouring,  167,  177,  178,  373 
Painting,  18 
Paints,  145 

Paint-spraying  Machine,  19 
Paper  Burlap,  Use  of,  162 

—  Rosin-sized,  108 

—  Saturated,  146 

—  Use  of,  32,  162 


438 


INDEX 


Parabola,  Sand  Curve,  81 
Paraffin  Defined,  419 
Paraffine  Defined,  419 

—  Naphtha,  419 

-  Oil,  Use  of,  163,  419 

—  Solution,  72 

—  Specific  Gravity,  387 

-  Use  of,  23,  28,  29,  145,  147,  162,  375 
Parapet  Walls,  116 

Patented  Cements,  23,  146 

—  Compounds,  145,  146 
Peeling  of  Stucco,  20,  26 
Pellet  Method,  204 
Penetrometer,  196 

Penetration    and    Temperature,     244, 

245 

Pennsylvania  Railroad  Tunnels,  335 
Percolation  Defined,  7 
Permeability  Defined,  7 

-  Effect  of,  67 

—  Test,  220,  221,  222,  223,  224,  226, 

227,  228 

Persulphate  of  Iron,  93 
Petrolene  Defined,  420 
Petroleum  Defined,  420 

—  Grease,  143 

-  Oil,  23,  146 

—  Specific  Gravity,  387 
Petrolic  Ether,  420 

Pig  Iron,  Use  of,  23,  143 

Pine  Oil,  420 

Pine,  Specific  Gravity,  387 

-Tar,  31,  142,  420 

Pitch,  Asphalt  Mixture,  111,  238,  239 

-  Defined,  420 

—  Linseed  Oil  Mixture,  236,  237,  238, 

239 

—  of  Roofs,  104,  105 

-  Quality  of,  49,  51,  52,  146 

—  Specific  Gravity,  387 
Pipe,  Coating,  420 

—  Grouting  Process,  86 

—  Mineral  Heating,  181 
Plane  of  Weak  Bond,  127,  142 
Planning  and  Estimating,  368 
Plaster  Bond,  420 

—  of  Paris,  33,  58,  111,  420 

—  Specific  Gravity,  387 
Plastering,  16,  18 
Plastic  Clav.  133 


Plastic  Roofing,  420 

—  Slate,  142,  420 
Plasticity  of  Bitumen,  32 
Plate  Steel,  147 

Plies,  Adhesion  Between,  34 

Pointing  Mortar,  126 

Porosity,  3,  7,  78 

Portable  Kettles,  50 

Portland  Cement,  Use  of,  24,  71,  73, 

74,  146,  147,  150,  420 
Post  Holes  Treated,  43,  44,  57 
Potash,  26 

Pouring  Pail,  167,  177,  178,  373 
Powdered  Metals,  27 
Powders  Finely  Ground,  66 
Practical  Tables,  379 

-  Tests,  26,  188,  229 
Precast  Joint  Filler,  128 
Preparation  of  Surface,  57,  58 
Prepared  Roofing,  112 

—  Shingles,  100,  101,  113 
Preserving  Concrete  Tanks,  317 

—  Liquids,  93 

—  Processes,  18 
Pressure  Tunnels,  357 
Priming  Coat,  30,  420 
Proportioning  by  Eye,  64 

-  Effect  of,  67 

—  Soap  and  Alum,  28 
Proprietary  Compounds,  18,  72,  146 
Protective  Concrete,  32,  36,  37,  56,  78, 

349 


Quaking  Consistency,  27 

Quasi,  Colloidal  Bodies  Defined,  420 

—  Soap  Bodies  Defined,  420 
Quick  Lime,  67 

R 

Rag  Felt,  32 

Railroad,  Concrete  Roadbed,  346,  347 

—  Drainage,  6 

—  Mezzanines,  344,  345,  347 

—  Viaduct  Waterproofed,  337 
—  Joint  Filler,  346 

Rain,  5 

Ready  Roofing,  112,  114 
Recipes,  Practical,  313,  425 
Red  Rope  Paper,  420 


INDEX 


439 


Heduced  Oils,  420 

—  Petroleum,  421 
Redwood  Shingles,  92 
Refined  Asphalt,  421 

—  Tar,  421 

Reinforced  Filter  Plant,  356 

—  Reservoir,  356 

—  Standpipe,  351 

—  Water  Tank,  357 
Reinforcement  Oxidation,  9 
Report  on  Waterproofing,  408 
Reservoirs,  13,  32,  329 

—  Gate  House,  325 
Residual  Oil,  421 

—  Petroleum,  421 

-  Tar,  421 
Resin,  151,  421 
Resinates,  67 

Retaining  Walls,  20,  31,  32,  325 

Rich  Mortar,  25 

Richardson  Method,  198,  204 

Ridge  Roll,  104 

Roadbeds  Waterproofed,  353 

Rock  Asphalt,  421,  52 

—  Excavation,  58 
Roman  Waterproofing,  1 
Rondout  Tunnels,  358 
Roof  Drainage,  118 

-  Gutters,  119 

—  Joints,  106 

—  Simplest,  91 
Roofers,  372 

-  Kettles,  172,  173 
Roofing,  91,  110,  319,  426 

—  Cement,  319,  421 

—  Cost  of,  91 

—  German,  96 
-Gravel,  110,421 

—  Modern,  92 

-  Mops,  176 

-  Nails.  397 

-  Paper,  319 

—  Selection,  91 
-Slag,  109,  110,421 

—  Spanish,  96 
Roofs  in  Tropics,  92 
Rosin,  145,  147,  421 

—  Specific  Gravity,  387 
Rubber,  Specific  Gravity,  387 
Rust  Joint,  144 


S 

Salamander,  33,  65,  181,  373 
Sal  ammoniac,  146,  147,  151,  421 
Sanborn,  Mr.  James  F.,  89 
Sand,  25,  50,  62,  71,  80,  85,  147,  375, 
421,  426 

-  Cement,  24,  85,  147,  151,  421 

-  Drying,  179,  180 

-  Heating,  181 

-  Wall,  58,  60 

Sandstone,  Specific  Gravity,  4,  387 
Saturant  in  Felts,  252,  253 

-  Fabrics,  252,  253 
Sawdust,  375 

Scientific  Proportioning,  3,  78 
Scratch  Coat,  22 
Screenings,  402 
Scuttle,  373 
Sea  Wall  Coatings,  24 

-  Water,  Effect  on  Concrete,  4,  8 
Seasoning  Concrete 

Secret  Compounds,  145,  146,  165 

Seepage,  12 

Self-densified  Concrete,  17,  68,  76 

—  Materials,  146 
Semi  Asphaltic  Oils,  421 

—  Petroleum,  421 
Service  Tests,  26,  323 
Sewage,  Effect  on  Concrete,  8 
Sewer  Leakage,  35 
Shale  Tiles,  95 
Sheathing,  146 
-Boards,  92,  100,  114 

-  Paper,  109 

Sheet  Copper,  94,  97, 146 

-  Iron,  123,  146 

-  Lead,  37,  45,  94,  104,  105,  132,  146 

-  Mastic,  38,  52,  53,  146,  421 

-  Metal,  147,  393 

—  Piling,  58 

—  Tin,  146 
Shingle  Roof,  92 

Shingles,  92,  93,  101,  104,  396 
—  Methods  of  Applying,  102,  103,  104 
Short,  Defined,  421 
Shovel,  373 
Sieves,  400 
Silicates,  66 
Silt,  Effect  of,  125 
Slack  Barrels,  373 


440 


INDEX 


Slag  Cement  Mortar,  24 

—  Roofing,  94,  109,  308,  310 
Slate,  Powdered,  31,  63,  111 

—  Shingles,  93 
Slates,  4,  387,  397 

Slip,  Tongue  Joint,  127,  128 

Slush  Coat,  22 

Smith  Ductility  Machine,  211,  212 

Smoother,  46,  177,  178,  373 

Snow,  5 

Soap,  28,  66,  74,  145,  147,  151,  375,  421 

—  and  Alum,  Action  of,  28 
Soda  Ash  Defined,  421 
Sodium  Chloride,  9 

—  Fluoride,  93 

—  Silicate,  93 

—  Sulphate,  83 
Softening  Point,  207,  208 
Soils  Solidified,  83 
Solvent,  Effect  of,  28,  29 
Soluble  Glass,  421 
Spading,  3 

Spalls,  Use  of,  56 
Special  Cements,  146 

—  Membrane,  45 

Specific  Gravity  of  Concrete^  4 
—  of  Materials,  4,  387 
—  Coal-tar  Pitch,  197 

Petroleum,  197 

and  Baumc,  381,  382,  383,  384, 

385 

—  Resistance  of  Concrete,  10 

of  Mortar,  tO 

Specifications,  426 

-  Asphalt,  267,  268,  269 
-Bridge,  298,  299,  300,  301,  302 

—  Caisson,  291 

—  Coal-tar  Pitch,  269,  270 

—  Concrete,  273,  305 

—  Creosote  Oil,  270 

—  Dampproofing,  273 

—  Fabric,  263,  265,  266 

—  Felt,  264, 

—  Floor,  303>  3Q4 

—  Foundation,  278 

—  Hydrated  Lime,  271,  272 

—  Integral  System,  274 

—  Masonry,  273 

—  Mastic  Pitch,  270 

—  Material,  263 


Specifications,     Railroad     Structures, 
293,  294,  295,  296,  297 

—  Requisites,  262 

—  Roof,  206,  207,  209,  306,  311,  312 

—  Stucco,  277 

—  Substructure,  279 

-  Subway,  280,  281,  282,  283,  284,  285r 
286 

—  Surface  Coating,  275,  276 

-  Tunnels,  280,  287,  288,  289,  290 

-  Waterproofing,  273 

—  Writing,  263 
Spruce  Shingles,  92 
Staggered  Type  Membrane,  41 
Standard  Methods  for  Bridges,  294 
Standing  Seam  Roofing,  106,  108 
Staves,  as  Fuel,  50 

Steam  as  Fire  Extinguisher,  50 

—  Insulation,  45 

Steam-pressure  Placing  Machine,  89 
Stearates,  28,  67,  72,  75,  143,  146,  147, 

152,  153,  421 

Steel  Plate,  Use  of,  163,  146,  367,  387, 
394 

—  Reinforcement,  12 
Stirrers,  177,  373 

Stone  Aggregate,  78-,  80;  163 

—  Average  Weight,  4 

—  Duplication  of,  3 

—  Preserving  Composition,  316 

—  Screenings,  86,147,  374 

-  Slab  Roof,  92 
Storing,  Effect  of,  48 
Structural  Bodyguard,  2 
Structures,  Bane  of,  3 
Stucco,  25 

Subaqueous  Tunnels,  362 
Subsurface  Structures,  350 
Subway  Asphalt,  421 

-  Pitch,  421 

Subways,  7,  32,  47,  48,  55,  354 
Suet,  145,  147,  153,  421 
Sulphuric  Acid,  8 

—  Anhydride,  8 

Supervision,  Effect  of,  3,  45,  76,  77,  81 
Surface  Coating  Compounds,  23,  25, 

30,  72 
System,  9,  IT,  18>  19,  26,  145,  315, 

323,  421 

—  Preparation,  33,  58 


INDEX 


441 


Swimming  Pool,  20,  25,  352 

Switch  Pits,  36 

Sylvester  Process,  17,  28,  421 


Tables,  Explanation  of,  379,  386 

Tallow,  Specific  Gravity,  387 

Tamper,  373 

Tank  Treatments,  24,  317 

Tar  and  Gravel  Heater,  175,  174 

-  Use  of,  141,  145,  147,  164,  422,  423 
Technical  Tests,  188 
Temperature,  Effect  of,  2,  4,    11,    125, 

241,  251 
Tensometer,  210 

-  Mold  for,  211 
Terne  Plate,  105 
Terra  Cotta,  37,  58,  387 
Terrazzo  Floor,  231 
Tests,  Asphalt,  189 

-Determination,  190,  191,  192,  194, 
195,  198 

—  Drop  Point,  205 

-  Ductility,  209 

-  Flash  Point,  191 

—  Flow  Point,  208 

-  Identification,  212,  213,  217,  218 

-  Practical,  219,  229,  231,  234 

—  Publications  on,  426 

—  Specific  Gravity,  190 

-  Waterproofing,  188,  189 
Texene,  422 

Thatch  Roof,  91 
Thawing,  Effect  of,  2 
Thermometric  Equivalents,  380 
Thompson,  Sanford  E.,  69 
Tiles,  52,  99,  146,  387 

—  Shingles,  95 
Timber,  Use  of,  22,  50 
Tin,  384,  393,  394 

-  Cutoffs,  134 

—  Drain,  33 

—  Flashing,  94 

—  Plate,  105,  106,  108 

-  Roofing,  92,  105,  108 
Tongue  and  Groove  Joints,  133 
Tools,  Applicability  of,  166 
Torch,  57,  178,  373 
Torpedo  Gravel,  422 

Trap,  Specific  Gravity,  4 


Treated  Materials,  147 

Trial  Mixtures,  80 

Trinidad  Asphalt,  143,  422 

Trough,  58 

Trowels,  182,  373 

Tunnels,  Grouted,  83 

—  Penn.   Railroad,  20,  29,  31,  32,  33, 

39,  326,  327 
Turpentine,  375,  387 
Tun-eUite,  422 

U 

Ultimate  Tensile  Strength,  12,  .125 
Uneven  Settlement,  2,  4,  13 
United  States  Bureau  of  Standards,  8, 

27,  68,  69,  71,  74 
Capital  Terrace,  340 


Varnish  Gum,  422 

Vibration,  Effect  of,  13,  67 

Vintaite  Defined,  422 

Viscosity,  422 

Viscous  Priming  Coat,  30 

Vitrified  Tibs,  6,  45 

Voids,  Determination  of,  7,  78 

-  Filling  Materials,  3,  146 
Volatile  Defined,  422 

—  Oil,  49 
Volumetric  Synthesis,  80 

—  Tests,  80 

W 

Walls,  58 
Water,  147 

—  Absorbent,  422 

-  Diverted,  84 

—  Effect  on  Fabrics,  254 

—  Ejecting  Grout  Machine,  87 

—  Evaporation,  77 

—  Gas  Tar,  164,  422 

—  Glass,  75,  422 

—  Repellent,  3,  67,  422 

—  Pressure,  18,  63,  392 

—  Specific  Gravity,  387 

—  Storage  Works,  323 

-  Table,  5,  422 

—  Universal  Solvent,  1 

-  Use  of,  22,  50,  99,  164 

—  Works  Reservoir,  328,  360 


442 


INDEX 


Waterproofers,  Graded,  370,  372 
Waterproofing,  Adaptability,  82,  422 

—  Applied,  323 

—  Art  of,  1 

—  Cements,  320,  321 

—  Compounds,  313,  314,  321,  322 

—  Economy,  16 

—  Fabrics,  426 

—  Failures,  124 

—  Implements,  166 

-  Materials,  145,  389,  426 

-  Mortar,  314 

—  Paste,  72 

—  Progress,  17 

—  Projections,  43 

—  Publications,  425 

—  Roof  Coverings,  395 

—  Specifications,  262 

—  Steampipes,  43 

—  Systems,  17 
Watertight  Roofs,  91 
Wax,  387 

Weak  Bond  Plane,  133 
Weather  and  Waterproofing,  66 
Weep  Holes,  6 


Weight  of  Implements,  373 

-  Materials,  374 
Wet  Surface,  66 
Wheel  Barrow,  181,  373 
Wood  Cores,  373 

—  Flour,  375 

—  Shingles,  92 

—  Spreader,  183 
Wooden  Tanks,  318 

-  Floor,  319 
Wool  Felt,  32 
Workmanship,  77,  81 
Wurtzelite,  422 


Yoke,  Pail  Carrying,  179 


Zinc  Borate  Paint,  93 

—  Chloride,  93 

—  Coefficient  of  Expansion,  387 

—  Cutoffs,  134 

—  Roofing,  106 

—  Sheeting,  105 

—  Specific  Gravity,  387 


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